Well you have to admire the technical skill to launch a missile from a Mach 5 craft.
To give people an idea of scale, thats .3 of a Mach number higher than the SR-71 unclassified top speed.
That said, no doubt the US have technology that is capable of much more.
Depends if the US have technical skills derived from "other folks" or not, some have said that the US has
anti-gravity technology but the physicists say this is well beyond us at present considering that if it is a fifth
force interaction then at the moment we have only barely nudged the handle on that particular door.
As it happens I've done some research in this area and it looks like antimatter is to some extent part
of the answer, though an incomplete one.
Zero point interactions in the Dirac field may lead somewhere but without a working theory of quantum gravity its
likely that we will simply find it won't work at a useful level that can be measured in the laboratory, let
alone something that can levitate a craft.
I did have some success with an early version of a spark gap Tesla Coil with a complex interacting field, but all it could do
is knock over a radio and only when overdriven to the point the CCFL circuits nearly melted down.
Another experiment yielded a window material that showed clear resistance drops above room temperature.