A History of Short Words

From the New York Times Crossword Puzzle

RAF

Sun, 27 Aug '23
Battle of Britain grp.
Sat, 17 Dec '22
Org. whose motto is "Per Ardua ad Astra"
Fri, 10 Jun '22
W.W. II Dambusters grp.
Wed, 10 Nov '21
Battle of Britain grp.
Wed, 10 Feb '21
Mil. branch of the U.K.