An arrangement between two countries, states, or other administrative regions, that allows free air travel of residents between them while otherwise keeping their borders closed to travellers from outside the bubble.

plural of flight bubble

(aviation) An empty or near-empty flight run by an airline to fulfill contractual obligations.

plural of flight instrument

(aviation, usually in the plural) A device that measures and displays data concerning one or more aspects of the situation of an aircraft, such as its altitude, attitude, airspeed, etc.

(nautical) The person at the foiling controls to operate the hydrofoils on a boat or ship / (aviation) An air traffic controller

(aviation) A device which records various performance parameters of an aircraft; it is designed to survive severe impact and fire, and, thus, help in finding the causes of an accident.

(philately) a philatelically inspired letter flown on the first flight of a new airline service.

plural of first flight cover

(aviation) A substitute ticket issued by an airline due to a schedule change or other disruption to their service, allowing travel on another airline.