Fantasy Flyers is a set of free miniatures wargames rules for aerial skirmishes. You can construct your own flyers
I think it would be a good alternate game if you own some of those old Man O’War flyers — the Dwarf Gyrocopter, Manticore Riders, Wyvern Riders, etc. You also could use 15mm flyers (although I can’t recall if I’ve ever seen a good variety of those), or possibly 25mm fantasy figures (but I think the distances may have to be modified for this).
Massive Voodoo has a tutorial on lighting your workspace.
In Clouds of Glory is a set of free wargames rules for World War One aerial combat.
Bloodlust is a set of free wargames rules for fantasy battles with 15mm figures. The author writes:
SUPREME WARLORD: BLOOD LUST is a set of rules designed to create massive battles using 15 mm Historical pre-1600 castings and/or Fantasy castings. The Blood Lust Series is an effort to get new players into historical and miniature gaming. The rules in this series will focus on combat and inflicting casualties because new players tend to understand blood flowing and the visual affect of depleting units. Morale and command control rules are a factor but do not dominate play.
In the fantasy version, the World is in the midst of conflict dominated by several races embarking on quests of global domination. Resistance has been fierce and costly to all sides causing the war to escalate into wars of Racial Extermination.