The Open Skies Agreement between the United States and the European Union, taking effect at the end of March, eliminates decades of restrictions on the trans-Atlantic airline market. It allows U.S. and EU airlines to operate to and from any European airport, and U.S. carriers will be able to fly within Europe and continue on to other destinations. This means big changes at London's Heathrow airport, which, since 1977, has been operating under an agreement that allows only four airlines — British Airways, Virgin Atlantic, American, and United — to fly between Heathrow and the U.S. Northwest, Continental, and Delta all plan to seek a toehold at Heathrow. In late March, Heathrow's new Terminal 5 will open as the new home to the vast majority of British Airways' flights.

In June, British Airways will launch a U.S.-EU subsidiary airline, called OpenSkies, with daily flights from New York to either Brussels or Paris and more routes to follow. Aer Lingus launched service early this year from Dublin to Washington, D.C.; Orlando, Fla.; and San Francisco. Aer Lingus also has a new partnership with JetBlue Airways. Starting April 3, passengers will be able to book linked flights between Ireland and more than 40 U.S. destinations, connecting through New York's Kennedy International.