Graham William Jenkins is a Young Leader with the Pacific Forum and a Senior Principal Analyst for strategic assessment with a major aerospace contractor.
One of the most valuable attributes of airpower in warfare is the ability to fly to anywhere from anywhere, avoiding terrain and hostile forces alike. But despite this seeming omnipresence, straightline “crow’s-flight” distances are illusory. A complicated patchwork of bilateral arrangements, open-skies regimes, and international legal frameworks divides the sky into national airspaces and flight information regions, projecting into low-Earth orbit itself in a straight line from territorial borders on the ground.
What this means for current and future aerial platforms is that aerospace engineers and designers must consider not only the most likely conflicts and use cases but also the respective basing options for those conflicts. It means that tracing a path from point A to target B does not tell the whole story and that political considerations may well lead to requirements for longer range aircraft or alternative rotation schema. International law offers answers to most overflight scenarios, but where these laws might conflict with perceived national interests in wartime, U.S. military planners will be forced to consider alternatives to otherwise “simple” mission routing.
Despite the global access it has enjoyed since the end of World War II, the United States has nevertheless been challenged on numerous occasions and denied the use of even friendly airspace for overflight. A RAND study on U.S. military basing overseas summarized some of these instances:
In 1958, Greece, Libya, and Saudi Arabia refused the U.S. overflight and basing rights for its intervention in Lebanon. . . . In 1962, Portugal and France denied U.S. overflight and base access because of Washington’s involvement in the Congo crisis; in 1967, Spain denied the United States use of its bases to evacuate U.S. nationals during the 1967 Arab-Israeli war; in 1973, Spain, France, Italy, and Greece refused to grant base access and overflight rights to U.S. planes lifting supplies to Israel; in 1986, Italy, Germany, France, and Spain refused to cooperate with a U.S. air strike on Libya by denying the U.S. basing rights or overflight for Operation El Dorado Canyon.1
Further access restrictions ranged from “limited overflight rights for U.S. Navy combat aircraft in the Persian Gulf region during the 1987–1988 Earnest Will escort operations to a rather tortuous negotiation process to gain Indian approval for transport aircraft overflight (and emergency divert airfield access) in support of Operations Desert Shield/Storm in 1990–1991.”2 In addition, throughout the spring of 2003, the United States engaged in a “will-they/won’t-they” debate with the government of Turkey before the execution of Operation Iraqi Freedom. Although eventually the Turkish parliament voted to allow use of their airspace, the Turkish general staff refused to allow U.S. special operations forces to enter Iraq via Turkish airspace. Instead, U.S. MC-130 aircraft turned to a route over “SAM Alley” in northern Iraq, and after one was hit by enough antiaircraft fire to require emergency diversion to Incirlik Air Base, the Turks relented and fully allowed overflight.3 These difficult negotiations reflect the general pattern of Turkish attitudes toward airspace permissions: begrudging at best and hostile at worst.
The United States has occasionally attempted to circumvent likely denials: In 2002, during the leadup to Operation Iraqi Freedom, the United States received permission to fly a KC-10 tanker over Austria but hid a pair of F-117 Nighthawks beneath its wings, within the tanker’s radar signature. After two fighters of the Luftstreitkräfte visually identified the presence of the F-117s, a diplomatic furor ensued.4 This move proved especially counterproductive: within a year, Austria was also denying U.S. forces in Germany use of the Austrian rail network and airspace to move troops closer to Iraq.5
The best-known U.S. airspace violation is certainly Operation Neptune Spear, the May 2, 2011, raid on Osama bin Laden’s compound in Abbottabad, Pakistan. The historical consensus, even at this close remove, has been that Pakistani authorities were notified of neither the raid nor the use of Pakistan’s airspace to insert Navy SEALs. In the aftermath, opinion polling showed near-universal condemnation for American unilateralism, with 85 percent of Pakistanis disapproving of the operation’s execution without Islamabad’s knowledge.6 The Abbottabad Commission, tasked with identifying the Pakistani shortcomings that had allowed U.S. forces to so thoroughly penetrate Pakistani airspace, heard from Pakistan’s deputy chief of the air staff that “the Abbottabad incident was indeed one of the most embarrassing incidents in the history of Pakistan” and that a combination of peacetime posture and trusting attitude toward the United States—which “was never expected to commit such a dastardly act”—had led to the incident.7 Such a mistake would not be permitted to happen again.
In short, the United States has been willing to violate sovereign airspace before—and will likely do so in the future—but whenever it has done so, the move has come with a cost.
Laws between nations are relatively clear on the issue of sovereign airspace. The 1944 Convention on International Civil Aviation, better known as the “Chicago Convention,” defines state aircraft as “aircraft used in military, customs, and police services” and explicitly declares that “no state aircraft of a contracting State shall fly over the territory of another State or land thereon without authorization by special agreement or otherwise, and in accordance with the terms thereof.”8 Thus, military aircraft must receive explicit permission from another country before flying over or landing in its territory. Note that there is no exception made or distinction drawn between peacetime and wartime, nor the intent of the aircraft. However, as some legal scholars point out, this “fundamental” principle is “subject to a few exceptions . . . such as right of transit passage, archipelagic sea lanes passage, entry in cases of distress, and force majeure.”9
Transit passage and archipelagic sealine passage are relevant to future missions and are also enshrined in the United Nations Convention on the Law of the Sea (UNCLOS), which expands the definition of sovereignty out from the shoreline: “The sovereignty of a coastal State extends, beyond its land territory and internal waters and, in the case of an archipelagic State, its archipelagic waters, to an adjacent belt of sea, described as the territorial sea. This sovereignty extends to the air space over the territorial sea” and further defines the territorial sea as up to 12 nautical miles from the coastal baseline.10 Beyond that are the high seas, over and through which aircraft and vessels have full freedom.
Thus far, the application of UNCLOS to overflight remains a simple matter: Military aircraft must obtain permission before overflying another country’s territory, including the territorial sea up to 12 nautical miles from the coast and any internal waters. However, it is one of the exceptions to this clause that is most interesting here: archipelagic sealine passage.
The United States, in its UNCLOS signing statement, interpreted that, in international straits and archipelagic sealines, “military aircraft may overfly in combat formation and with normal equipment operation.” Even more important, “a State bordering an international strait may not suspend transit passage through international straits for any purpose, including military exercises,” and “the right of archipelagic sea lanes passage cannot be impeded or suspended by the archipelagic State for any reason.”11 This has particular importance for future operations in the Western Pacific Ocean, home to the two archipelagic states—Indonesia and the Philippines—as well as a likely arena of coming military competition.
Having established the legal foundations of military overflight, there remain several areas of current interest and future concern. Both operational planning and materiel procurement will have to account for the possibility—if not likelihood—of denied access in the future, adding distance to flight routes and challenges to aircraft recovery, as well as requiring longer range capabilities. Several countries crop up in the literature regularly as “repeat offenders”—those “proven to be access problems time and time again.”12 These countries have been more likely than others to deny the United States overflight permission or otherwise challenge its access. Of greatest relevance in the coming years will be Turkey, Indonesia, and the Philippines, as well as much of Southwest and South Asia.
Turkey. Turkey is a perennial disappointment in U.S. (and North Atlantic Treaty Organization) strategy, and as the Erdogan administration has grown more assertive and less deferential to its allies, it has begun weaponizing its airspace, which lies at a crucial crossroads for international aviation. Between 1945 and 2014, Turkey denied U.S. contingency access requests 16 times.13 And in just the past 5 years, Ankara has
- refused overflight to allied French and British airborne warning and control system aircraft in 201514
- closed the airspace around Incirlik Air Base following the coup attempt against President Erdogan in 2016, stranding U.S. aircraft on the ground15
- denied overflight permission to a Chinese medical aircraft chartered by Cyprus to deliver COVID-19 relief supplies to Nicosia in May 2020.16
All of this, however, is well within Turkey’s sovereign rights—meaning that, without any legal solutions, the safest course of action is to plan on having no access to Turkish airspace, especially in peacetime and likely even wartime (barring involvement by allied Turkish forces themselves). This poses challenges for missions originating in the Mediterranean and North Africa, particularly those flying north and northeast (toward the Black Sea). The relationship with Turkey is due for revision as-is, and the present lack of access ought to be a prime consideration for future statecraft.
Western Pacific. With the U.S.-China competition poised to take center stage in the coming decades, access to the Western Pacific has assumed prime importance for defense planning. In addition to its traditional bases in Japan and Guam, the United States has explored new (or expanded) partnerships with the Philippines, Vietnam, Australia, Thailand, and Singapore. Yet all these partnerships face the same challenge: distance.
The closest current basing partners to the South China Sea are the Philippines and Vietnam; however, U.S. relations with Manila have been severely strained in recent years, and Hanoi—though contesting the Paracel Islands with China—is unlikely to have any interest in a wider regional conflict (for instance, in the eastern Spratly Islands closer to Luzon). In the East China Sea, South Korea has no appetite for a war with China, and Taiwan would of course do everything possible to avoid unnecessary provocation.
The availability of specific bases throughout the region will determine the distances aircraft would have to travel to reach target areas. In recent years, U.S. planning has tended to assume universal access to bases and airspace alike, but as history and international law demonstrate, the United States might well be more constrained than it has previously believed.17 This reality must be factored into future capability requirements.
The United States faces the distinct possibility that China would place undue pressure on other regional partners to deny it overflight and access, necessitating complicated routes across much longer distances. The challenges presented by this problem are numerous, and their solutions increasingly unpalatable:
It is not too much of a stretch to imagine that nonbelligerents, under PRC [People’s Republic of China] pressure and having curtailed access to their territory, might conceivably restrict permission to overfly their country as well. This would severely limit the avenues of approach of airpower and reinforcements flowing into theater as they are forced to detour around the airspace of erstwhile partners. This in turn would allow the PRC to concentrate its forces—backed up by a mainland-based reconnaissance strike complex—on these narrow vectors, such as the Luzon and Singapore straits. . . . The United States will have to examine the difficult prospect of violating the sovereignty of nonbelligerents in a time of war. There may well come a point when the joint force will have to seize key positions along the South China Sea periphery—for example, in the Philippines, Indonesia, or Malaysia—for short durations in order to facilitate operations.18
All these challenges will affect design and capabilities of future aircraft. Even with unfettered base access, denial of overflight would force aircraft flying from Guam to divert north (or south) around the Philippines, from Australia over Papua New Guinea (or even further east), or from Singapore (northwest and then east), to try and obtain Thai and Vietnamese airspace permissions. Such access cannot be taken for granted. While U.S. defense planning may have been able to overlook or assume Southeast Asian access in the past, its increasing reliance on Australian bases will make that an oversight it can ill afford.
Australia. Australia’s defense relationship with the United States has become closer in recent years. Canberra is increasingly alarmed by China’s growing assertiveness and willingness to engage in confrontation, and to that end it has taken steps that increase U.S. access to Australian military bases. The most prominent among these bases are Darwin, home to both the Royal Australian Air Force (RAAF) and the Robertson Barracks (itself hosting a rotational 2,500-strong U.S. Marine Air-Ground Task Force), and RAAF Base Tindal, 175 nautical miles southeast of Darwin, quickly emerging as one of Australia’s most critical air bases.19 The U.S. air presence in Australia has been steady, with the Enhanced Air Cooperation program putting on numerous U.S.-Australian exercises each year, primarily involving manned fighter and lift aircraft.20
As the U.S. presence in Australia continues to grow, it is likely that unmanned aircraft would constitute part of future rotational deployments and thus would be operating toward targets to the north. The same also applies to the growing U.S. presence in Singapore at Changi Air Base. Missions from Tindal or Changi would, at a glance, need to traverse Indonesian airspace, which is not as straightforward as one might hope—despite the relative clarity of international law on the subject.
Indonesia. Indonesia has taken a hard nationalist line on its airspace for years, to the point where it has refused to join regional open skies regimes. Jakarta has a longstanding debate with Singapore over who should manage the Riau Islands flight information region (FIR), which includes Singapore as well as large portions of Indonesia and has been under Singaporean administration since 1946, when granted by the International Civil Aviation Organization. Over the past decade, Indonesia has been increasingly vocal about taking control of the Riau Islands FIR on the grounds of sovereignty, which would essentially give it veto power over U.S. (and Singaporean) operations from Singapore.21 Given its recent history of intercepting aircraft straying even a few nautical miles over Indonesia territory—including the Riau and Natuna Islands themselves—it is unlikely that the United States would find leniency from Jakarta.22
Indonesia’s airspace ambitions do not end with the FIR. In 2018, Indonesia issued regulations over airspace management that included an assertion that “the Government could establish an Air Defense Identification Zone/ADIZ” encompassing a much broader swath of territory than otherwise provided for by international law.23 As Evan Laksmana writes:
Article 9 defines an ADIZ as “specific air spaces above the land and/or waters established to identify aircraft for the purposes of state defense and security.” It identifies Indonesia’s “Airspace” and “Jurisdictional Airspace” as areas where the ADIZ could apply. The former refers to the “sovereign airspace” above Indonesia’s territory, while the latter is defined as the airspace above the exclusive economic zone, continental shelf, and contiguous zone, where it has “sovereign rights” prescribed by international law.
This last claim may raise eyebrows, as no specific international law grants sovereign rights to the airspace above an exclusive economic zone, nor is there one delimiting ADIZs.24
It is unclear how enforceable such an ADIZ would be or, indeed, how Indonesia would treat its archipelagic sea lines under such a regime. From a capabilities standpoint, Indonesia lacks both the radar network and airpower required to detect, much less intercept, all aircraft above such an enormous area. But if Jakarta were to ignore international legal precedent and require permission—or even just notification—for military aircraft flying above international sea lines, the implications would be troubling. (Indeed, the political consequences would be deleterious: It might provide sufficient cover for China to declare its own ADIZ in the South China Sea.25) The United States would be faced with the unpalatable options of cooperating with illegal restrictions, ignoring them, or avoiding Indonesian airspace altogether, necessitating a thousand-nautical-mile detour over Papua New Guinea (assuming it is willing to grant overflight rights—a dubious assertion in light of longstanding China–Papua New Guinea ties).
Even without an ADIZ, the UNCLOS archipelagic sea line regime has never been put to the test in wartime. While peacetime transit of military aircraft might be relatively unobjectionable to Jakarta—and to this date, the United States has not flown combat missions from Australia—the use of that airspace for long-range strike or other kinetic missions may engender a wholly different reaction. Indonesia may fear the reaction of China should it “allow” its airspace to be used. For the purposes of future Singaporean- and Australian-based aircraft, it will be critical in the coming years to pay attention to Indonesia’s stance on its airspace and to react accordingly. The distinct possibility of no Indonesian overflight should be taken seriously.
Southwest Asia. Having completed its withdrawal from Afghanistan, the United States has extremely limited air-basing options in South and Southwest Asia, whether in pursuit of nonstate actors or in support of an interstate conflict. With access to Bagram and Kandahar out of the question, it is now necessary to consider alternatives in case of future contingencies in the region.26 From where, for instance, would the bin Laden raid have been launched if not from Afghanistan? While Gulf bases provide a possible launch location for strike and intelligence, surveillance, and reconnaissance missions, they are less useful (and likely, their host nations less willing) as mobilization points for special operations forces and other ground troop incursions, particularly given the probability of traversing hostile terrain.
One of the current regional success stories can be found in Oman. To avoid the Strait of Hormuz and close proximity to Iran when traveling eastward from Gulf bases in Qatar, Bahrain, and the United Arab Emirates, U.S. aircraft must overfly Oman. This overflight regime has been a tremendous success, with former U.S. Central Command Commander Joseph Votel testifying to Congress that there were more than 5,000 aircraft overflights a year over Oman.27 But this success story also points to a vulnerability: Were Oman to begin denying overflight, the United States would be forced either to risk a confrontation with Iran or to take an incredibly circuitous route every time it wished to move an aircraft in or out of the theater.
Without U.S. access in Afghanistan, Gulf bases are the closest option to the Indo-Pakistani border. And without Omani overflight permission, that already-lengthy route becomes outright perilous, especially if the contingency being supported involves a less-than-friendly Pakistan. Clearly, if the United States wishes to continue playing a persistent role in this region, it must either find alternative bases or develop very-long-range aircraft that can operate from locations like Diego Garcia with only limited aerial refueling.
“Freedom” of the Skies
Even with numerous geographic restrictions on U.S. access and overflight, it is arguable that there is no need for concern: If the shortest path for American aircraft means the United States must violate a country’s airspace, it can and will do so with impunity. While not necessarily incorrect from a capability standpoint, such a move still poses severe reputational risks to the United States. Failure to uphold international law and its own word would not endear the United States to any future partners, and running roughshod over the rights of smaller powers would give any adversary an advantage in the global struggle for influence. Violating a country’s airspace could even have the effect of diminishing the cause of the United States in the eyes of its own citizenry—often the death knell for successfully prosecuting any conflict.28 Even where a state does grant overflight permission, the deceptive assertion of a denial can be cited in the court of international opinion, such as Russia’s false claim that Poland blocked overflight rights for a planeload of medical equipment bound for Italy.29 Should the converse be used as a tool of influence—falsely claiming, for example, that a country allowed the United States use of its airspace—sufficiently negative reactions might dissuade others from actually doing the same.
Likewise, while the United States is virtually unparalleled in military capability, it is not omnipotent, and other states are not remaining idle in their antiair capabilities. Several U.S. partners are acquiring sophisticated air defense systems like the Russian S-400, including Turkey, India, and Saudi Arabia, while in Southeast Asia, Israel has been supplying Vietnam and the Philippines with modern air defense radars.30 Should the United States attempt to ignore airspace restrictions and forge ahead with combat missions regardless, the consequences might well be destructive. This would be especially true if the United States employed older, less stealthy platforms—and be doubly devastating if those platforms were manned.
Thus, to avoid having to make an impossible choice, most of the airspace solutions will lie in the realm of the diplomatic. Such actions as securing basing and overflight rights on a bilateral basis, amending existing status of forces agreements, and strengthening existing mutual defense treaties will have to be the cornerstone of any successful approach. Preparing messaging campaigns and adequate explanation for those rare instances in which diplomacy is insufficient will be another valuable tool.31 But perhaps it would be more useful to assume the worst and plan for it accordingly. Assuredly U.S. global supremacy will not last forever, and neither will its unchallenged rule of the skies. If new aircraft have longer ranges, more versatile basing options, and more flexibility in their operational areas, the challenge of overflight and airspace in the coming years and decades can indeed be surmounted. JFQ
1 Michael J. Lostumbo et al., Overseas Basing of U.S. Military Forces: An Assessment of Relative Costs and Strategic Benefits, RR-201-OSD (Santa Monica, CA: RAND, 2013), 103n8.
2 Adam B. Siegel, Basing and Other Constraints on Land-Based Aviation Contributions to U.S. Contingency Operations (Alexandria, VA: Center for Naval Analyses, March 1995), 6.
3 Walter L. Perry et al., eds., Operation Iraqi Freedom: Decisive War, Elusive Peace, RR-1214-A (Santa Monica, CA: RAND, 2015), 109–110.
4 Jamie Hunter, “The Time When the USAF Got Caught Trying to Sneak F-117s Through Austrian Airspace,” The Drive, July 21, 2020.
5 Lostumbo et al., Overseas Basing of U.S. Military Forces, 102n4.
6 Julie Ray and Rajesh Srinivasan, “Pakistanis Criticize U.S. Action That Killed Osama Bin Laden: Many Believe Pakistan Will Be Less Safe from Terrorism,” Gallup, May 18, 2011.
7 Abbottabad Commission, Final Report, January 2013, 142–145.
8 International Civil Aviation Organization (ICAO), Convention on International Civil Aviation (“Chicago Convention”), doc. 7300/9, 9th ed. (Montréal: ICAO, 2006), pt. 1, ch. 1, art. 3b-c.
9 Michel Bourbonniere and Louis Haeck, “Military Aircraft and International Law: Chicago Opus 3,” Journal of Air Law and Commerce 66, no. 3 (2001), 895n35.
10 United Nations General Assembly, “United Nations Convention on the Law of the Sea (UNCLOS),” December 10, 1982, pt. II, §1, art. 2.1–2; §2, art. 3.
11 “Message from the President of the United States Transmitting the United Nations Convention on the Law of the Sea, with Annexes, and the Agreement Relating to the Implementation of Part XI,” U.S. Senate Treaty Doc. 103-39, 103rd Cong., 2nd sess., October 7, 1994, 19, 22.
12 Stacie L. Pettyjohn and Jennifer Kavanagh, Access Granted: Political Challenges to the U.S. Overseas Military Presence, 1945–2014, RR-1339-AF (Santa Monica, CA: RAND, 2016), 137.
13 Ibid., 139–140.
14 “Turkey Denied Overflight Permission for UK and French Surveillance Aircraft,” Nordic Monitor, December 30, 2019, available at <https://nordicmonitor.com/2019/12/turkey-refused-overflight-permits-to-the-uk-and-france-surveillance-aircrafts/>.
15 John Vandiver, “Turkey Closes Airspace over Incirlik, Grounding U.S. Aircraft at Base,” Stars and Stripes, July 16, 2016.
16 Agence France-Presse, “Cyprus Says Turkey Denied COVID-19 Supply Flight Airspace Entry,” Yahoo! News, May 13, 2020, available at <https://au.news.yahoo.com/cyprus-says-turkey-denied-covid-19-supply-flight-154335631--spt.html>.
17 Pettyjohn and Kavanagh, Access Granted, xiv–xvi.
18 Blake Herzinger and Elee Wakim, “The Assumption of Access in the Western Pacific,” CIMSEC: The Center for International Maritime Security, June 2, 2020.
19 See “RAAF Base Tindal,” Royal Australian Air Force Web site, available at <https://www.airforce.gov.au/about-us/bases/northern-territory/raaf-base-tindal>.
20 Seth Robson, “U.S. Air Power Is Growing Alongside Marine Corps in Australia’s Northern Territory,” Stars and Stripes, November 4, 2019, available at <https://www.stripes.com/theaters/asia_pacific/us-air-power-is-growing-alongside-marine-corps-in-australia-s-northern-territory-1.605860>.
21 “Singapore Responds to Former Indonesian Officials’ Comments on Flight Information Region,” Straits Times, December 12, 2017, available at <https://www.straitstimes.com/asia/se-asia/spore-responds-to-comments-by-ex-indonesia-air-force-officers-over-flight-information>.
22 David Mumford, “Indonesia Is Intercepting Aircraft—Outside Their Airspace,” OpsGroup, January 16, 2019, available at <https://ops.group/blog/indonesia-is-intercepting-aircraft-outside-their-airspace/>.
23 Evan Laksmana, “Is an Indonesian Air Defense Identification Zone Forthcoming?” Asia Maritime Transparency Initiative, Center for Strategic and International Studies, April 10, 2018, available at <https://amti.csis.org/indonesian-adiz-forthcoming/>.
25 Euan Graham, “Southeast Asia’s Neglected Navigational and Overflight Challenges,” The Interpreter, February 27, 2017, available at <https://www.lowyinstitute.org/the-interpreter/southeast-asia-s-neglected-navigational-and-overflight-challenges>.
26 Stephen Losey, “Lawmakers Want to Know How U.S. Will Keep Up Terror Fight After Afghanistan Pullout,” Military.com, April 20, 2021, available at <https://www.military.com/daily-news/2021/04/20/lawmakers-want-know-how-us-will-keep-terror-fight-after-afghanistan-pullout.html>.
27 General Joseph Votel, commander, U.S. Central Command, statement, The Posture of U.S. Central Command; Terrorism and Iran: Defense Challenges in the Middile East, Hearing before the Senate Armed Services Committee, House of Representatives, 115th Cong., 2nd sess. (March 13, 2018), 32.
28 Herzinger and Wakim, “The Assumption of Access in the Western Pacific.”
29 Juliusz Sabak, “Poland Issued No Airspace Restrictions for the Russian Humanitarian Aid Flights Headed to Italy. Coronavirus Employed by Kremlin as Means of Propaganda,” Defence24.com, March 24, 2020.
30 Alvite Singh Ningthoujam, “The Military-Security Dimension of Israel-Southeast Asia Relations,” Middle East Institute, January 7, 2020, available at <https://www.mei.edu/publications/military-security-dimension-israel-southeast-asia-relations>.
31 Herzinger and Wakim, “The Assumption of Access in the Western Pacific.”