Brandywine Airport (ICAO: KOQN, FAA LID: OQN, formerly N99) is a public-use general aviation airport in West Goshen Township, Pennsylvania, United States, three miles northeast of West Chester. It is designated as a reliever airport and a regional general aviation airport by the FAA. It is privately owned by the New Brandywine Airport Club Inc, with a single fixed-base operator (New Brandywine Aero, Inc.), aircraft repair, as well as flight training in both fixed-wing and rotary aircraft. The American Helicopter Museum and Education Center is located adjacent to the airport, with taxiway access.

The airport identifier was previously N99 until it was changed to OQN in 2007. The airport does not currently have an IATA identifier.