Definition: Aircraft by wing design
i) Fixed wing aircraft
An aircraft fitted with fixed wings to provide the lift required to sustain flight
ii) Rotary wing aircraft (helicopters)
An aircraft fitted with a set of wings, rotating in a largely horizontal plane to provide both lift and forward propulsion.
iii) Tilt wing aircraft
An aircraft powered with turboprop engines with wings, which can be tilted during operation in order to achieve shorter take off and landing distances
Draft Glossary on Air Transport Statistics, 2001