A passenger jet flies past the FAA control tower at Reagan National Airport. (Cliff Owen/Associated Press)

The swap deal has been underway for several years, but was delayed by the government’s desire that other airlines be able to buy some landing rights held by the two airlines. Under the deal Delta would give US Airways 42 slots it holds at National in return for 132 slots at LaGuardia. Delta also would pay US Airways $66.5 million.

National slots are in demand because travelers like the airport's close proximity to downtown Washington.

The airlines would be required to sell eight slots at Reagan and 16 slots at LaGuardia to other airlines. A slot allows an airline to land and takeoff an airplane from the airport.

In making the announcement, the Transportation Department said it would allow public comment for 30 days before giving final approval to the deal. Comments can be made online at regulations.gov.