An aircraft is
|“||[a] vehicle, manned or unmanned, capable of sustained flight in the atmosphere by forces exerted upon it by the air.||”|
|“||[a]ny machine that can derive support in the atmosphere from the reactions of the air other than the reactions of the air against the Earth's surface.||”|
- NATO Intelligence, Surveillance, and Reconnaissance (ISR) Interoperability Architecture (NIIA), Vol. 4: NIIA Terms and Definitions A-5 (Sept. 2005) (full-text).
- Unmanned Aircraft System Operations in UK Airspace–Guidance, at 4.