Reported Inventory, Use, and Cost of Federally Owned Aircraft, GAO-17-73R: Published: Oct 31, 2016. Publicly Released: Oct 31, 2016: “Federally owned aircraft are operated by agencies to fulfill their diverse missions. As of July 2016, 11 federal agencies owned 924 aircraft, excluding those that are loaned/leased/provided to other entities. This inventory included:

• 495 airplanes,
• 414 helicopters,
• 14 unmanned aircraft systems (commonly known as drones), and
• 1 glider.

Of the 11 civilian agencies, the Department of State owned the most aircraft (248), and the National Science Foundation owned the least (3). Agencies reported spending approximately $661 million to use and maintain owned aircraft in fiscal year 2015. Agencies reported using aircraft for a variety of purposes, including law enforcement, scientific research, firefighting, and other activities. Of the 924 owned aircraft, 88 were non-operational in July 2016. Agencies consider an aircraft to be non-operational when it cannot economically be returned to airworthiness. Non-operational aircraft can be used for parts, put on display, or be destroyed, among other things. Aircraft that were owned and operational as of July 2016 were used for an average of 275 flight hours in fiscal year 2015. These aircraft ranged from 0 flight hours to 1,279 in fiscal year 2015. Flight hours is the most common metric for aircraft use, although some aircraft also report alert or research and development hours. Agencies reported spending approximately $652 million in fiscal year 2015 to use and maintain aircraft that were owned and operational as of July 2016. Agencies typically report their costs in four cost categories: maintenance, overhead, fuel/oil, and crew. Agencies do not report the cost of depreciation.”