[dingaling]

Indeed, and first flew in 1964. Note that the follow-on MiG-31 was considerably slower despite sharing the general aerodynamic platform.

Since then Vmax has been declining, as the aerodynamics and mechanical complications ( e.g variable intake ramps ) of higher-Mach flight were determined to be less useful than transonic manouevrability and sustained supercruising.

The exception to this trend has been the superfighter category ( F-111, F-14, F-15, F-22, Su-27 ) which have maintained the same ~ M2.5 Vmax due to their specific role. Yes, even the F-111 was meant to be a fleet fighter.

But none have pushed up past the heady M3.0 level that was routinely broken by a series of prototypes in the 1960s.