Aer Lingus and its OneWorld alliance partner, American Airlines, have been granted code-sharing rights by the US Department of Transportation for the four existing Aer Lingus gateways in New York, Boston, Chicago and Los Angeles and a new service to Baltimore/ Washington.

Aer Lingus can offer its customers services to more destinations using American Airlines' global network. Aer Lingus says this will effectively introduce a new major US airline into the Irish market.

Aer Lingus will begin code-sharing with American Airlines this summer and the Baltimore/Washington service will begin in September.

Aer Lingus group chief executive Mr Larry Stanley said the new gateway "will give Aer Lingus access to this key destination and will boost business and leisure travel by linking Ireland for the first time with the capital of the United States and its hinterland".

A code-sharing agreement linking the reservations systems of Aer Lingus and British Midlands came into effect in March.