Word Origin & History
airline1813, "beeline, straight line from place to place" (as through the air, rather than over land; in later 19c., esp. in ref. to railways that ran direct from city to city in the U.S., instead of meandering from town to town in search of stock subscriptions as early railways typically did), from
air (1) +
line. Meaning "public aircraft transportation company" is from 1914.