1923 -- The Beginnings of Inflight Refueling

The air service first demonstrated inflight refueling in June 25, 1923, and in August of that year Lts. Lowell H. Smith and John P. Richter set a new world's record by staying aloft for 37 hours and 15 minutes in a DH-4 over San Diego with the help of refueling from another DH-4.