WASHINGTON (Reuters) -The U.S. Transportation Department on Tuesday finalized its awards of five new daily round-trip flights from Washington Reagan National Airport to major airlines.

The flights at the busy airport in Arlington, Virginia, outside the nation's capital were mandated under legislation signed in May by President Joe Biden. American Airlines Delta Air Lines, United Airlines, Southwest Airlines and Alaska Airlines all are receiving new flights after the department made tentative awards in October. Carriers are to start new flights within 90 days.

Congress in May required the Transportation Department to select five daily flights to expand service to cities without direct service and boost competition in markets with existing service.

The Washington region has three major airports, but Reagan National is closest to the U.S. Capitol and downtown Washington. Because of its short runways, the airport's main runway is the busiest in the U.S., and Reagan is the 24th-busiest U.S. airport by passengers.

The flights chosen include a Delta flight to Seattle, a Southwest flight to Las Vegas and an American Airlines daily flight to San Antonio, Texas, which would connect the seventh-largest U.S. city to the Washington-area airport. The other new flights are Alaska Airlines to San Diego, the largest market without direct flights to Reagan National, and a new United Airlines flight to San Francisco.

The Transportation Department rejected a proposal by JetBlue to add a flight to Puerto Rico.

Congress in 1966 said airplanes could only fly to destinations within a 650-mile perimeter of National Airport, with some exceptions, but decades later expanded the flight distance to 1,250 miles. Since 2000, Congress has approved 25 daily flights, including the five new ones.

The fight over the new flights was a key reason an aviation reform bill was delayed for more than six months.