 Garrison rejoined the 4th Fighter Group (now a component of the 4th Fighter Wing) at Andrews Air Force Base, Maryland, in April 1947, was promoted to captain, and became part of the U. S. Air Force when it became an independent service on September 18.Garrison organized and led a jet aerial demonstration team for the 4th FW, flying P-80 Shooting Stars, and participated in the first official delivery of air mail by jet to celebrate the 30th anniversary of air mail on May 15, 1948.Using the same route as in 1918, Garrison delivered a packet from Washington, D.C. to New York City in a 28-minute flight.