From the back of the book:
The Warbirds World War II Sourcebook lets you recreate the deadly aerial battles of the Second Wolrd War using Outrider Studios’ Rapidfire Dogfighting rules.
Fly RAF Spitfires against Messerschmitt BF 109s in the Battle of Britain, or have US Navy F4F Wildcats square off agains Japanese Zeros at the battle of Midway. You can even play a bombing
crew risking the skies over Germany, or strafing the jungles of Indochina.
The World War II Sourcebook contains the stats for 25 of the most famous aircraft of the war, conversion rules for naval ships, trains, and tanks, and rules modifications to make Warbirds into a gritty war game.