Blackbird SR-71, Mach 3.5. Loses fuel when on ground and only sealed in high altitude :D

:D It had a good run for 33 years before it was retired. Now officially LM are focusing all their money and time on the F-35 Lightning II & unofficially on the TR-3B "Aurora" (Mach 8 to Mach 12)

They also are planning a SR-72, a hypersonic jet

I'll slightly let you in on a fact of the industry. Because of most countries "limited" military budget. The UN, NATO, The DoD, Pentagon and UK's MoD make billions/trillions "disappear" into the "black budget"; The SR-72 has been in the air already at least since 2019. They always put on this show to suck more money out of the taxpayers/governments.

they always try to get more money. But the SR-72 should become real, but not a classic airplane, more a drone "to fight satellites" or something like this.