Starting March 28, the skies will literally open up for Europe-bound U.S. travelers. That’s when the new Open Skies Agreement between the United States and the European Union takes effect, lifting bilateral restrictions on flights between the two regions. Treating Europe in effect as a single country, the transatlantic accord allows U.S. airlines to expand nonstop service from their hubs to coveted destinations, especially those favored by high-paying business travelers, such as Heathrow.

Jean-Philippe Perol, who acts as US chairman of the European Travel Commission and director of Maison de la France, welcomed the new liberalization:

“This is the latest step in the melting of borders in Europe and between our two continents for the benefit of travelers,” he said. “First the euro simplified currency exchange, then the Schengen Agreement melted borders within Europe. With Open Skies, we are removing the barriers and restrictions to transatlantic travel, and the consumer will be the real winner, with a greater choice of gateways to European destinations.”

Until now, only British Airways, Virgin Atlantic, American Airlines and United Airlines could operate transatlantic flights from Heathrow. Starting March 30, Air France will start daily nonstop service from Los Angeles to Heathrow. British Airways, for its part, is launching a new airline called OpenSkies in June that will fly nonstop JFK to Paris or Brussels, using a B-757 in a three-class configuration of 82 seats, with only 30 in economy class and the rest in business with lie-flat beds and premium economy.

British Airways' Chief Executive Willie Walsh said: "This is an exciting new venture for us and we're confident that it will be a great success as we build on the strength of British Airways' brand in Europe and the US.  By naming the airline OpenSkies, we're celebrating the first major step in 60 years towards a liberalized EU/US aviation market, which means we can fly between any EU and US destination."

American Airlines is doubling frequency on their route into London Stansted Airport and Eos Airlines is adding a new route from Newark Liberty International Airport into Stansted. US Airways, Northwest Airlines, Continental and United are all launching new service to Heathrow, and Zoom Airlines is launching new seasonal routes to London Gatwick from Fort Lauderdale and San Diego.

European carriers, for now, seem to prefer to add more codeshare partnerships. Lufthansa will codeshare with United Airlines on 28 weekly flights from Paris Charles de Gaulle, and Air France will sell two flights from Brussels and 13 direct flights between the UK and Ireland and the US operated by Delta. In addition, bmi plans to place its code on United flights from Heathrow to Chicago O’Hare, Los Angeles, Washington Dulles, San Francisco and Denver.

Meanwhile, Aer Lingus and JetBlue Airways have inked a deal that, while not exactly codesharing, is quick and easy for both carriers. The deal links both their websites and allows passengers to make a single Internet booking on aerlingus.com to and from Ireland and more than 40 continental U.S. destinations. Passengers will connect at JetBlue’s home base at JFK in New York and fly onward without having to check-in baggage again. The cost of the two flights will be added as if booked separately.

Although logic dictates lower prices as a result of increased competition, high fuel prices and added airport surcharges, at Heathrow, for example, are tempering any immediate fare decreases. Be that as it may, travelers are flocking to Europe, undeterred even by their decreased buying power abroad. Indeed, the FAA expects to see transatlantic passenger growth of about seven percent for the next four years on U.S. and foreign carriers, with U.S. carriers increasing international capacity more than eight percent in 2008.

Here’s a summary of new transatlantic flights and routes, as well as seasonal changes: