What is the fastest Boeing military jet? The question is somewhat broad and depends on what one includes. As yet, Boeing has not developed and brought into service a single original manned fighter jet. Most of its jet-powered military aircraft were inherited from its acquisitions and mergers over the years (particularly Rockwell and McDonnell Douglas). It has completely rebuilt and redesigned the old F-15 and F/A-18 aircraft, effectively producing new aircraft, but they are still based on pre-Boeing platforms.

There is also much more to military jets than just manned fighter jets. Other aircraft to consider include autonomous air-launched hypersonic vehicles and strategic bombers. Boeing has also worked with NASA to produce a number of high-speed experimental air vehicles. Here is what to know about the first military jet aircraft Boeing built or otherwise has ownership or responsibility for today.

Fastest Experimental Unmanned Jet

The fastest unmanned and experimental military jet ever produced by Boeing was the X-43A Hyper-X, built in partnership with NASA. NASA writes, « NASA made aviation history with the first successful flights of a scramjet-powered airplane at hypersonic speeds—greater than Mach 5, or five times the speed of sound. » NASA says that being scramjet-powered, the X-43A is able to operate more like an airplane, unlike rocket-powered space shuttles.

It was able to travel at ultra-high speeds within the atmosphere. The X-43 was not able to take off by itself and was instead carried aloft by a B-52 mothership. After detaching from the B-52, a booster rocket, which was a modified first stage of the Pegasus rocket, was launched to the required speed and altitude. After that, the rocket was discarded, and the X-43 flew using its own scramjet. Today, the X-43 stands out as the fastest jet-powered aircraft on record. It managed to set a world record of around Mach 9.6.

It is the fastest air-breathing aircraft ever flown, and it meets the definition of a jet aircraft even if it looks like something else to many people. A total of three were built. The first test took place in 2001, although it failed. The second test took place in 2004 and was successful. A third test also took place in 2004 and broke the Mach 6.83 record set by the second test.

McDonnell Douglas X-36

The McDonnell Douglas X-36 was built for the Tailless Fighter Agility Research Aircraft program. It was built by NASA at a 28% scale of a possible fighter aircraft. Only two prototypes were built, and they were flown by onboard pilots. The design was to reduce weight, drag, and the aircraft’s radar cross-section while increasing range, survivability, and maneuverability. The research aircraft’s first flight took place in 1997, the same year Boeing absorbed McDonnell Douglas and inherited the X-36 program.

The Air Force Museum says, « The first X-36 flight occurred in May 1997, and the flight test program met or exceeded all of the project’s goals — a remarkable achievement. » However, this was the end of the Cold War, funds had dried up, and the US lacked a peer competitor. These tailless fighter jet designs were dropped, although they seem to be making a comeback with sixth-generation fighters like the Boeing F-47.

Another aircraft built by Boeing worth mentioning here is the unmanned Boeing X-51A Waverider. It was a successful hypersonic scramjet demonstrator that achieved Mach 5.1, just over the generally accepted Mach 5 threshold for hypersonic flight. The aircraft was carried by the Boeing B-52 Superfortress mothership. Four were built, with the first flight in 2010 and the final flight in 2013.

Boeing X-47 6th-Gen Fighter

In the early 2000s, Boeing competed with the X-32 demonstrator for the program that would become the F-35 fighter jet. The demonstrator was able to fly about Mach 1.6 (like the Lockheed F-35), but it lost the competition. In early 2025, Boeing was selected as the winner for the manned fighter jet component of the NGAD program.

Much remains secret about the F-47. Indeed, it remains unclear what the aircraft will look like. Only two official partial renders of the jet have been released, and these are believed to feature misdirections and may not be truly representative of the aircraft. According to Trump, when he announced Boeing as the winner, the fighter jet will be able to fly at above Mach 2.

When the F-47 enters service around the end of the decade, it will be the first fighter jet designed and built by Boeing to actually enter service. All other fighter jets, like the F-15 and F/A-18, were inherited through its acquisition of McDonnell Douglas. That said, the latest variants, namely the F-15EX and Super Hornets, are essentially new aircraft designed and built by Boeing, only superficially resembling their forerunners, the F-15C and Hornet.

McDonnell Douglas/Boeing F-15 Eagle / F-15EX

Boeing is currently producing two types of fighter jets, the F-15EX and the F/A-18 Super Hornet, although the final Super Hornets are expected to be delivered in 2027. The F-15EX has the distinction of being the fastest Boeing fighter jet currently in production. Not only that, but the twin-engined F-15 is also the fastest fighter still in production in the United States. It has a top speed of Mach 2.5+ and was designed for the air superiority role, although it has since become a multirole fighter jet.

By contrast, the F-35 Lightning II is considered the most advanced fighter jet in the world, but it only has a top speed of around Mach 1.6. It was even slowed from a target of Mach 1.8 to 1.6 during its development. This was for a number of reasons. One is that supersonic speeds are rarely useful for fighter jets in combat or even for reaching the combat zone. High speeds reduce maneuverability while also guzzling the aircraft’s fuel, meaning it can’t spend long in the conflict area or might not even have the range to reach it in the first place.

Another issue with supersonic speeds is that heat friction will lower the F-35’s stealth. It’s also worth pointing out that the F-15 was not originally a Boeing aircraft; it was developed by McDonnell Douglas, but then absorbed by Boeing as part of the 1997 merger between the two companies. The F-15EX has the distinction of being the final fourth-generation fighter jet that will be ordered by the US military. The USAF no longer orders the F-16 (although it remains in production for export), and the final order for the Navy’s F/A-18 has been placed.

Rockwell B-1 Lancer

Like the F-15, the Rockwell B-1 Lancer strategic sweep-wing bomber was not developed by Boeing. It was developed by North American Rockwell (later Rockwell International) and was later acquired by Boeing. Today, Boeing is the prime contractor for the United States Air Force in maintaining and upgrading its B-1 Lancers. Lancer prototypes were originally able to fly at as much as Mach 2.2 at high altitudes.

The aircraft was designed at a time when the Air Force wanted a bomber that could outrun enemy air defenses, but the development of improved SAMs rendered this redundant. That is why the next generation of bombers, the B-2 Spirit and now the B-21 Raider, are subsonic. « You can’t run, but you can hide. » The Rockwell was reduced to a top speed of Mach 1.25 at high altitude, although its low-altitude speed was increased to Mach 0.92.

By contrast, the upcoming Northrop Grumman B-21 Raider is believed to have a top speed of Mach 0.8+. The aircraft is not intended to be a superfast bomber flying in and out before anyone can respond, as in practice, this is ineffective against modern air defense; the B-21 is to be a ninja flying unseen, leaving explosions in its wake. This doesn’t mean the original doctrine of the B-1 is completely dead; Lockheed’s Skunk Works is developing an unmanned successor to the SR-71 called the SR-72 that will fly at hypersonic speeds. This will theoretically allow it to outrun air defense.

Other High-Speed Aircraft Inherited By Boeing

As Boeing absorbed North American down the line, Boeing can also take credit for the North American X-15 rocket airplane that flew on the edge of space in the 1950s. One of its pilots was none other than Neil Armstrong. That aircraft retains the world record for the fastest manned aircraft, reaching a top speed of Mach 6.7. However, as a rocket plane, it wasn’t a jet plane.

In the same vein, Boeing inherits the canceled North American XB-70 Valkyrie strategic bomber. Only two prototypes of that incredible aircraft were built, and they had a top speed of an impressive Mach 3.1. Boeing also inherited the McDonnell Douglas F-4 Phantom II fighter jet. These are noted for having a top speed of around Mach 2.2, and while they were retired in 1996 from the combat role by the US, they remain in service in Turkey as well as in limited use in Iran. They are still in service with Greece, but these are set to be retired.

Other aircraft Boeing can lay claim to include the Banshee, Demon, and Voodoo, all developed by McDonnell in the early Cold War. North American military jets it can claim include the iconic F-86 Sabre, the F-100 Super Sabre, and the F-107 Ultra Sabre (which didn’t enter service). When it comes to the much-loved A-10 Warthog, Lockheed Martin is now the prime contractor (it took over Fairchild Republic), but Boeing manages production and wing replacements.