Aer Lingus was established in 1936 and is the flag carrier airline of Ireland. The company's first aircraft was supplied by Blackpool and West Coast Air Services, with which it was associated. Aer Lingus' first route was between Dublin and Bristol (Whitchurch) Airport. Routes expanded to include Liverpool and Croydon, before the outbreak of war in 1939 led to Aer Lingus being restricted to flying to Manchester's Barton Aerodrome and Liverpool, when security allowed. In 1945 services to London resumed. Through the late 1940s and 1950s expansion continued with flights to Rome, Amsterdam, Brussels and New York. Flights to Boston launched in 1960.

Originally majority owned by the government, the airline was privatised between 2006 and 2015. It became a wholly owned subsidiary of IAG, International Airlines Group.