To supercruise is an aviation term. An aircraft that can supercruise is able to attain and maintain supersonic level flight without using afterburners. The first U.S. fighter to supercruise will (theoretically) be the F-22 Raptor Advanced Tactical Fighter, currently in low-rate production.

The SR-71 Blackbird engines were almost entirely afterburning, especially for takeoff. The nacelles themselves (not the J-58 jet engines in them) provided nearly all the thrust at high speeds; the inlet spike and nacelle mouth 'shaped' the airflow into precise shockwaves of high supersonic speed. The fuel burn outside the engine, in the nacelle (afterburner) made the nacelle into a 'near-ram-jet' with the engine mostly getting in the way.

WolfKeeper provides needed correction: the Concorde (and its Soviet counterpart the Tupolev 144) did, in fact, have supercruise. The Concorde, however, used 'low-level augmentation' - essentially, afterburners - during takeoff and in order to accelerate past Mach one - in order to spend as little time as possible in a high-drag flight regime. Although afterburners use more fuel, the ability to quickly traverse these less-efficient flight regimes meant an overall fuel savings, and the Concorde would then turn off reheat and supercruise at its normal Mach two without afterburners.