A supersonic biplane would apparently create less drag than a single-wing aircraft (such as the Concorde) and thus consume less fuel, and most importantly it would create much smaller sonic booms.

Spike Aerospace’s S-512 aims to revolutionize supersonic flight by eliminating the loud sonic boom that grounded Concorde’s overland routes. Designed to cruise at Mach 1.6–1.8, the sleek jet ...