How fast does the F-35 fly?

Lockheed Martin sets the F-35 Lightning II's maximum speed at Mach 1.6, about 1,900 km/h (1,200 mph) at altitude, for all three variants: the conventional A, the short-takeoff-and-vertical-landing B, and the carrier-based C. The figure is set by design, not by available power. The Pratt & Whitney F135 engine is the most powerful ever fitted to a fighter, producing about 191 kN of thrust with afterburner, but the F-35 carries its weapons internally to preserve its radar signature, and that wide fuselage, together with an air intake with no moving parts, isn't built for the temperatures and pressures of Mach 2. On top of that, the tail's radar-absorbent coating suffered damage during prolonged high-speed afterburner testing, which led to limits on supersonic flight time for the B and C variants in the late 2010s.

In operation the F-35 cruises subsonically, around Mach 0.8-0.9, carrying more than 8 tonnes of internal fuel in the A variant, giving it a range that an F-16 only matches with external tanks. It doesn't have supercruise in the F-22 sense, though test pilots have described stretches of about 150 miles (240 km) at slightly supersonic speed without afterburner after accelerating. Its concept is different: detect first using the AESA radar, the distributed electro-optical system and sensor fusion, fire from a distance, and avoid being forced into a tail chase or close combat. In that scheme top speed matters less than the ability to arrive undetected.

The comparison with the F-16, which exceeds Mach 2, or the F-22, which tops Mach 2.2 and sustains Mach 1.5 without afterburner, makes the F-35 look slow, and the debate has followed the programme since its start. But fourth-generation fighters only hit those figures clean, without missiles or tanks, while the F-35 at Mach 1.6 flies armed and stealthy. Its generation rivals, Russia's Su-57 and China's J-20, claim around Mach 2, though those figures aren't independently verified. Sixth-generation designs in development are aiming at range, sensors and accompanying drones rather than speed records, confirming the trend the F-35 started.