| SNN is the second-largest airport in Ireland, located at the mouth of the River Shannon in Co. Clare, near the cities of Limerick and Ennis. The Irish government designed Shannon in the 1930's to be Ireland's international airport, and signed an agreement with the United States that all trans-Atlantic flights to and from Ireland would be legally required to stop there. The new airport was first opened in 1942, and scheduled flights began in 1945 with an American Overseas Airways DC-4 stopover. Soon, Pan Am, TWA, and BOAC were making regular stops at Shannon.
Despite the fact that its surrounding population was rather small and impoverished, Shannon quickly rose to become one of Europe's leading airports. At the time, it was the westernmost major airport in Europe, and so it was a major hub for trans-Atlantic flights in the days when it was impossible to fly airliners directly from America to the Continent. Even after longer-range aircraft were developed, Shannon continued to be used as a refueling point for Aeroflot's shorter-range Ilyushin Il-62 and Il-86 aircraft.
In 1947, Brendan O'Regan opened the world's first airport duty free at Shannon, under a license from the Irish government. This operation was later taken over by Aer Rianta, which opened a similar duty free at Dublin Airport, eventually becoming the airport authority for both airports, as well as a duty free concessionaire at several airports across Europe.
The airline and air freight business at Shannon helped to kick-start the industrial development of Clare and Limerick, culminating in the opening of the Shannon Industrial Free Zone in 1964. Both counties saw a boost in tourism from their proximity to the Gateway to Ireland.
Then, in 1993, the US-Irish bilateral was renegotiated, and Shannon lost its legal status as Ireland's international airport. Aer Lingus, Delta Air Lines, and other trans-Atlantic carriers began operating direct flights from Dublin. Initially, many were worried that Shannon would dry up under the new laws, but much to the contrary, the airport continued to grow and attract new customers, this time because of Ireland's stellar Celtic Tiger economy.
Today, Shannon sees about 2 million passengers a year, or about half the population of the Republic. Aer Lingus and Ryanair are its largest airline tenants, serving airports across Europe. The following trans-Atlantic routes are still being operated today:
Westbound passengers complete U.S. immigration procedures in Shannon, instead of at their destination.
The airport has two runways, 06/24 (3,200 m) and 13/31 (1,720 m).
see also: http://www.snn.aero - http://www.iol.ie/~discover/snnfl.htm | 
