The US lacked an independent air force service branch during World War II. Like Japan, air power was handled by the United States Army Air Force and the Navy’s airwing (the US Air Force was established post-war in 1947). The US Army Air Force (USAAF) grew to become not only the largest US Air Force ever but also the largest air force in the world in WWII. Countless thousands of American aircraft were built (and lost) in World War II. Here are five of the top USAAF aircraft of WWII.