The U.S. Air Force inducted its first fourth generation combat aircraft, the F-15 Eagle heavyweight fighter into service in 1976, providing a very signifiant improvement over the prior Vietnam War era generation where the F-4E Phantom had represented the service’s heaviest and most widely used fighter. The F-15’s performance was far ahead of the F-4 across the spectrum, from speed and altitude to endurance, situational awareness and most drastically its manoeuvrability at both high and low speeds, while the fighter also carried eight air to air missiles up from the Phantom’s original six. The Eagle had one major shortcoming relative to the Phantom, however, which was its much higher operational costs and maintenance requirements. While the F-4 was a very expensive aircraft to operate for its time, and as a result saw relatively few exports with most clients being delivered the cheaper and lighter F-5, the U.S. Air Force could still afford to form the backbone of its fleet using the fighters. This was not the case for the F-15, however, which required the Air Force to acquire a lighter and cheaper fighter in parallel and in much larger numbers – the F-16 Fighting Falcon.
The F-16 used the same F110 engine as the F-15, but in single rather than twin configuration meaning it had only half the thrust. Its radar was considerably smaller and weaker, comparable to that of the Soviet MiG-23ML that had entered service, but the fighter itself could not fly anywhere near as high or as fast as the MiG-23 let alone the F-15. The F-16’s endurance nevertheless exceeded that of the F-4, and while slower and unable to fly as high it otherwise improved on the Phantom in all areas of performance including in terms of maintenance requirements and operational costs. The F-16 and F-15 were thus highly complementary, with the former filing out most units and providing a somewhat unremarkable but still robust capability for air to air combat, while the latter formed elite units tasked with engaging the most capable fighters in an enemy air force and if needed penetrating deeper into enemy airspace. This was reflected in the roles the two were assigned in the U.S. Air Force’s first major post-Vietnam air campaign, Operation Desert Storm against Iraq in 1991, which saw the more numerous F-16s held back from any engagements against Iraqi top end MiG-25 interceptors and MiG-29 fighters while the F-15s were tasked with tackling these more aircraft. The F-16 would likely have struggled against both of them despite the superiority of American pilots and their access to support from E-3 AWACS jets which the Iraqis lacked.
The F-15’s elite status was also reflected by its armaments, with the F-16 for years provided no beyond visual range air to air missiles meaning even against Soviet third generation jets such as MiG-23s it faced a significant disadvantage. When F-16s began to belatedly field AIM-7 Sparrow missiles, providing semi active radar guidance, the F-15 was already set to deploy the much more capable AIM-120 with active radar guidance. Many F-16 units operated for years or even decades with no beyond visual range capabilities.
The F-15 and F-16 are the oldest fighters in the world to still be in production today, albeit primarily for export and in the F-16’s case largely to less developed American defence clients with smaller budgets such as Bahrain, Slovakia and Bulgaria. The F-16 saw a production run of over 4,500 by 2010, with the producer Lockheed Martin expressing confidence in 2020 that the fighter could exceed 5000 units. There were indictions in early 2021 that the U.S. Air Force could resume F-16 purchases due to major issues with its replacement program the F-35, although later statements by officials indicated this was unlikely to materialise with a growing number of defence officials in both the U.S. and abroad highlighting that the Falcon would very soon be obsolete. The production figure for F-16s excludes the Japanese F-2, which is very closely based on the F-16 but with much higher use of advanced composite materials, larger wings and different avionics and sensors. The F-15, meanwhile, has seen approximately 1,700 built – around 500 of which are derivatives of the F-15E Strike Eagle variant. Both fighters saw the large majority of units produced in the 15 years from 1976 to 1991, with a sharp contraction in production after the Soviet collapse as well as a contraction in the number of operational units.
The discrepancy in numbers produced reflects both the F-16’s much wider use in the U.S. Air Force, as well as its much greater popularity on export markets. The F-15 had only six export clients while the F-16 had 25 — with Italy also having leased the aircraft for a brief period. The F-16 is not only much cheaper both to purchase and to operate, but is also widely seen was more cost effective with modern variants compensating for their radar’s small size with sophistication and for a short range with the integration of conformal fuel tanks. In terms of combat performance the F-15 is far superior, particularly in air to air engagements, but this is only assuming that equivalent variants are being compared. The weakest F-15s, the Israeli F-15A/B jets from the 1970s, would be very overwhelmingly outmatched by modern F-16 variants such as the F-16 Block 70 and F-16V sold to Taiwan, the F-16E in the United Arab Emirates, or Japan’s derivative the F-2. Even F-16s from the 1990s would likely post a serious challenge for such old Eagles to tackle. The F-15 has had one very significant advantage which ensures that it receives more foreign interest today that the F-16, which is that it has no successor in production due to the very early termination of the F-22 Raptor program that was meant to succeed it. The F-16, by contrast, has seen its successor the F-35A not only widely produced but also marketed widely for export which effectively strips it of any market share from higher end clients.
It is notable that while the U.S. Air Force and NATO member states more generally have relied on the F-16, and other fighters from similar weight ranges such as the Rafale and Eurofighter, to form the bulk of their units, Russia moved in the opposite direction after the end of the Cold War with almost all fighters and interceptors in service today being heavyweights – and those few that are not being medium weight MiG-29s mostly inherited from the Soviet era. This means Russian fighters will on average be much longer ranged, have over double the thrust and deploy much larger sensors and significantly more ordinance than their Western counterparts, which partly compensates for how overwhelmingly outnumbered the Russian Air Force would be in a conflict with the alliance. China has followed the same trend, albeit less radically, acquiring its first heavyweight fighters in 1991 and comprising a growing portion of its fleet from them primarily advanced Flanker derivatives such as the J-16 as well as the new fifth generation J-20.
The U.S. Air Force partly compensates by modernising its F-16s, with the latest F-16V variants being more than a match for some of Russia’s older heavyweights such as the Su-27SM despite being much smaller. It also deploys elite units of F-15s and F-22s which, much as was the case in the Gulf War, are expected to be employed to tackle higher performance enemy fighters. F-16s will meanwhile engage older aircraft or take on a greater burden in air to ground operations. The F-15 is expected to remain in service significantly longer than the F-16 largely due to the F-22’s failure to replace it, with the U.S. Air Force having over 100 on order which are yet to be delivered after resuming orders in 2018, and will also outlive the F-22 with the relatively small numbers produced set to be retired decades early. The F-16, meanwhile, will still play a central role in the U.S. Air Force well into the 2030s, with the F-35 not expected to be ready for even medium intensity combat for many years to come and currently restricted to a very limited initial operating capability with over 800 performance issues – resulting in the Pentagon continuing to delay authorising it for full scale production.