AVIATION : U.S., Britain Take Step to Expand Air Accord : Relations: ‘Mini’ deal allows a second carrier to fly the Chicago-Heathrow route. Talks are scheduled for July.

The United States and Britain have struck a “mini” deal to expand bilateral air services as a first step toward further liberalizing their aviation accord, the Transportation Department said Monday.

The pact allows a second U.S. carrier, expected to be United Airlines, to fly from Chicago to London’s Heathrow Airport and additional flights by British Airways on its existing Philadelphia-London route. American Airlines is the only U.S. carrier now flying the Chicago-Heathrow route.

Transportation Secretary Federico Pena said the United States has long recognized the need to end curbs on air traffic between the two countries and that “this agreement represents an important first step.”

But equally important, he said, the British have agreed to talks beginning in July to further liberalize their air accord, with a pledge to expedite an agreement.

The United States has long sought such liberalization, including open access to Heathrow, considered vital for U.S. carriers serving Britain and beyond to continental European.

The United States has been repeatedly rebuffed by Britain, which has argued that Heathrow, the hub for British Airways, is already overcrowded.

U.S. airline officials said the new pact does little for American carriers that want unrestricted access to Heathrow.

“The big disappointment we have here is there is no opportunity for Delta to provide its own service into Heathrow,” said Bill Berry, a spokesman for Delta Air Lines.

American Airlines, which has sought more British access, criticized the new pact and said it gives too much to the British.