The US Federal Aviation Administration has firmed the proposed slot swap at Washington National and New York LaGuardia airports between Delta and US Airways.
Approval by the FAA culminates a two-year effort by the carriers to gain approval for the deal, which has been altered several times to appease regulators.
US Airways is transferring 132 slot pairs at LaGuardia to Delta while Delta is ceding 42 slot pairs at National to US Airways. Delta is also paying US Airways $66.5 million in cash.
The approval is conditional on the carriers divesting eight slot pairs at National and 16 at LaGuardia to ensure consumer protection.
After granting tentative approval of the deal in July, US regulators drew criticism from both Southwest and JetBlue Airways, who argued that US Airways and Delta should be required to divest more slots than stipulated by FAA.
But in its final approval of the deal FAA stated one of the more "compelling benefits" articulated by Delta and US Airways was that development of LaGuardia as hub by Delta "will lead to enhanced service to small communities, and improved competition versus other east coast hubs, including United's Newark hub and US Airways' hub in Philadelphia".