An aerogram; a letter sent by airmail.

a local region of low atmospheric pressure, or a local downward current; especially one that causes an aircraft to lose height suddenly

The bilateral agreements concerning international air travel defined by the Chicago Convention in 1944, covering such topics as overflight, stopovers, and passenger carriage.

(idiomatic) Not yet resolved, finished, answered, decided or certain.

Used other than figuratively or idiomatically: see up, in, the, air.

An equal mixture of nitrous oxide and oxygen, used as a mild analgesic and anaesthetic, particularly during childbirth, for dental procedures, and in emergency medicine.

(idiomatic, broadcasting) An unintended interruption in a broadcast during which nothing is transmitted: a silent period on radio or a silent period with no picture on television.

(usually in the plural) A two-handed gesture resembling quotation marks.

A device used to remove contaminants from the air.

A pump that moves air either into or out of something.