The US Department of Transportation (DOT) has granted Southwest Airlines authority to begin one round-trip flight between Ronald Reagan Washington National airport in Washington DC and Houston Hobby airport in Texas.
The agency announces today that it has granted Southwest two slot exemptions to operate the flights, which must begin by 5 August.
The exemptions, which were also sought by JetBlue Airways and US Airways, became available after Spirit Airlines moved its Fort Lauderdale flights from Washington National to Baltimore-Washington International airport in September 2012.
JetBlue had proposed flying from Washington National to Jacksonville in Florida and US Airways had proposed a flight to Oklahoma City in Oklahoma.
The slots permit airlines to fly routes within a 1,250 mile radius of Washington National.
"Southwest's service will provide air travellers with a new, low-cost option when they fly between Reagan National and Houston," DOT secretary Ray LaHood says in a statement.
United Airlines is the only other carrier that flies non-stop from National to Houston, but it serves the city's George Bush Intercontinenal airport. United flies the route five to eight times daily.
Southwest currently serves St. Louis in Missouri and Austin in Texas from Washington National, and its AirTran Airways subsidiary flies from Washington National to Milwaukee in Wisconsin, Atlanta and the Florida cities of Orlando and Fort Myers.