The resistance to forward supersonic flight may be reduced by sweeping the wings .

During takeoff and landing, when the aircraft is at high angle of attack, a powerful vortex system develops above a swept wing. This system contributes to the portance of the wing by creating a low pressure area which pulls up the aircraft.

The airfoil shapes designed for the future supersonic aircraft project are tested under these flight conditions by numerical simulation on powerful computers. The computations are validated in the wind tunnel on models where the vortex structures are analysed by detailed velocity measurements using laser technology.