The federal government has regulated "slots," or authorization to operate flights, at Reagan airport and New York's LaGuardia Airport because of limits on runway capacity at the facilities. Flights from both airports have traditionally been capped at 1,250 miles, though the transportation department has authorized a number of exemptions
in recent years.
Thompson said Tuesday that the slot for the flight from Reagan to Jackson, Miss., could not be traded. If U.S. Airways decides to stop operating the flight, he said, the DOT would solicit another airline to provide service between the cities.