Yes, another letter in the endless string of one liners. But sailors are simple folk and like to make things easy on themselves.

F-- First letter in the Navy aircraft designation, indicating a fighter plane

F -- Columbia Aircraft Corporation (manufacturer's symbol)

F1 -- Commander-in-Chief, Plans Division (USN)

F2 -- Commander-in-Chief, Combat Intelligence Division (USN)

F3 -- Commander-in-Chief, Operations Division (USN)

F37 -- Commander-in-Chief, U.S. Fleet

F4 -- Commander-in-Chief, Readiness Division (USN)

F -- Fairchild Aircraft, Ltd. (Canada) (manufacturer's symbol)

2F -- Two-seater Fighter Aircraft (Naval)

F -- Fitted as Flagship (suffix to plane designation); as: PB2Y-5F

F -- Grumman Aircraft Engineering Corporation (manufacturer's symbol)

F -- Officer designation for Fighter Director (used as suffix)

F -- Fighter Field

F -- Fireman

F -- Fixed (a continuous steady light)

F -- Fleet Reserve

F2 -- Fleet Reserve, 4 or more years

F3 -- Fleet Reserve, 16-20 years

F5 -- Fleet Reserve, 20 or more years

F -- Freight Boats (Army)

F -- French

F -- Frequency

F -- Office of Finance and Supply; Chief, Office of Finance and Supply (USCG)

Some of these are still used, mostly the Fleet Reserve and of course F for fighter. The aircraft company’s addreviations were almost all used during World War II, ie F4-F. If another company made a Wildcat they would add their letter after the F4. This happened more on the Torpedo planes, TBF was made by Grumman, TBM made by General Motors.