What does the B stand for in B-17 and B-24 and the P in P-38 stand for?
The B in B-17 and B-24 stand for Bomber and the P in P-38 stands for Pursuit. The Air Force changed the ‘pursuit’ designation to ‘fighter’ after WW2 which is one reason you may have noticed P-51s being referred to as F-51s in some text. The above answer is a paraphrase of Luc Hemelaer’s response to an 8th AF Message Board query for February 27, 2003.