American transcontinental airmail service begins. The route between San Francisco and Mineola, N.Y., is flown in 14 segments by pilots flying US-built de Havilland DH-4s. The first flight, made mostly in bad weather, takes 33 hours, 20 minutes.
The KC-Z4, a blended wing body tanker concept being developed by startup JetZero, could fuel larger groups of aircraft at longer range to hold more targets at risk, company officials say.