Who funds the development, acquisition, and sustainment of all U.S. military aviation?

The correct answer is that Congress funds the development, acquisition, and sustainment of all U.S. military aviation. This is primarily because Congress holds the power of the purse and is responsible for authorizing and appropriating federal funds for military expenditures. Through its legislative authority, Congress approves the budgets presented by the Department of Defense, which include allocations for military aviation programs.

While the Department of Defense plays a critical role in planning and executing aviation-related projects, it ultimately requires Congressional approval for funding. Additionally, the President may propose budgets and defense priorities but does not have the final say on funding without Congressional approval. The military branches themselves do manage operational budgets and specific projects within their own scopes, but these are funded from the larger appropriations determined by Congress.