Along with conducting independent air operations, the United States Air Force provides air support for land and naval forces and aids in the recovery of troops in the field. As of 2020[update], the service operates approximately 5,500 military aircraft and approximately 400 ICBMs. The world's largest air force, it has a $179.7 billion budget and is the second largest service branch of the U.S. Armed Forces, with 321,848 active duty airmen, [f].