> The Concorde relied on an afterburner to achieve supersonic flight, so it burned a ton of fuel.

Wiki says: https://en.wikipedia.org/wiki/Supercruise

    > Supercruise is sustained supersonic flight of a supersonic aircraft without using afterburner.

    > Concorde routinely supercruised most of the way over the Atlantic

Real question: How many in-production/operation engines in world can fly supersonic without afterburners? I think it is only a handful, all insanely expensive and backed with squillions of dollars of gov't/military money. And, the maintenance cycle must be out of this world expensive.