The national airline of Ireland. The name is a vaguely anglicised version of "Aer Loingeas", which means air fleet. Obviously at the time of the company's foundation (1936), nobody considered the obvious cunnilingus jokes.
Slight dodgy name notwithstanding, Aer Lingus is a fairly popular airline, generally noted for not treating its passengers like dirt. Compare Ryanair. The company runs flights to dozens of destinations in Ireland, Europe and the USA, and is part of the oneworld alliance with airlines such as British Airways and American Airlines.
The Irish government owns about 25%, Ryanair owns another 25%, and the remaining 50% is floated on the Dublin and London Stock Exchanges.