NASA's X-59 experimental aircraft has made its highest and fastest flights so far, expanding its operational range and progressing towards supersonic flight. The aircraft reached new altitudes and speeds of 43,000 feet and 528 to 627 mph during test flights on April 10 and 14, marking a significant increase from its previous altitude of 32,000 ft. Future flights will also examine the performance of its controls, loads, structural dynamics, and subsystems such as hydraulics, fuel, avionics, landing gear, and more. The X-11 is part of the Quesst mission, which aims to enable commercial, faster-than-sound air travel over land.