1) Fitness to fly 2) Soundness 3) Suitability for flight 
Airworthiness is the measure of an aircraft`s suitability for safe flight. Certification of airworthiness is initially conferred by a certificate of airworthiness from a national aviation authority, and is maintained by performing the required maintenance actions. The application of airworthiness defines the condition of an aircraft and supplies ....
[n] - fitness to fly
noun fitness to fly; `the plane received a certificate of airworthiness`
A term used to describe both the legal and mechanical status of an aircraft with regard to its readiness for flight.