... But typically carry only about 3 minutes worth of fuel...
Not sure what the current official record for sustained hypersonic flight is, but it's measured in just a couple-three minutes last I saw.
NASA and the USAF ran a successful test of the Boeing X-51 Waverider in 2013.
It detached from its solid-fuel booster at 3200 mph and accelerated under its own power to 3400 mph, which is a bit more than one mile per second. It flew under power for 210 seconds, and returned telemetry data for 370 seconds of flight.
That flight marked the end of the X-51 program, because Barack Obama felt that we shouldn't have a Waverider until everyone else can have a Waverider.