Other than vehicles with a detached
shock wave, all aircraft heat up more the faster they move. From the NASA book Facing the Heat Barrier: A History of Hypersonics [1]:
At Mach 3 and higher, there was the Lockheed SR-71 that cruised at 85,000 feet. The atmosphere at such altitudes, three times higher than Mount Everest, has a pressure only one-fiftieth of that at sea level. Even so, this airplane experienced aerodynamic heating that brought temperatures above [260C] over most of its surface.
The SR-71 Blackbird gets to 260C
over most of its surface. Aluminium
anneals (softens) at 177C (alloys can be higher)
making it unsuitable as a material for use on the outside of the
Blackbird. The Blackbird used titanium instead.