Fast Play Jet Combat is a set of free wargames rules for 1/600 aircraft on a hex grid. Interestingly, it requires a d100 die. If you don’t have one handy (and who does), you can do the same thing with two d10s in different colors.
aircraft
Fokker Fodder
Fokker Fodder is a set of free wargames rules for World War One aircraft battles. The rules are designed for both single battles, and for campaigns.
Crimson Eagles Pulp Air Combat Rules
Crimson Eagles is Michael Reitz’s mash-up between the old FASA Crimson Skies pulp aircraft rules and the Canvas Eagles WWI rules.
Knights of the Sky WWI Aircraft Rules
Knights of the Sky is a set of free wargames rules for WWI Aircraft.
Fast Large Air Combats
Fast Large Air Combats is a set of free wargames rules for WWII air combat game using 1:144 or 1:100 scale miniatures. The rules are designed so that a single player can control multiple aircraft.