The DOT and the Federal Aviation Administration (FAA) have granted a joint waiver request of Delta Air Lines and US Airways to allow the two carriers to swap slots at New York LaGuardia Airport and Ronald Reagan Washington National Airport. Under the plan, now more than two years old, US Airways would transfer to Delta 132 slot pairs at LaGuardia in exchange for 42 slot pairs at Reagan National, route authority to operate flights to Sao Paulo, Brazil, and a $66.5 million cash payment.

The October 7 waiver, made public yesterday, carries various conditions, including that the carriers dispose of 16 slots at DCA and 32 slots at LGA to “eligible new entrant and limited incumbent carriers.”

Meanwhile, the Department of Justice continues its investigation into whether or not US Airways’ acquisition of slots at DCA might prove anticompetitive.

The carriers have presented the DOT with an analysis of the claimed benefits of the transaction, and asserted that changes in the economy and structure of the aviation industry at DCA and LGA since 2010 have dramatically mitigated what the DOT viewed as potentially damaging consequences of the original transaction.

The airlines list among those changes the market penetration of low-cost carriers (LCCs) at both DCA and LGA by JetBlue, AirTran and Frontier Airlines and the potential for increased competition resulting from the Southwest-AirTran merger.  The carriers assert that the recent United/Continental merger enhanced United’s “competitive profile” at both Newark Liberty International Airport (EWR) and Washington Dulles International Airport, as well as at LGA and DCA. Delta also states that the transaction will allow it to establish a hub at LGA and address the competitive advantage secured by American Airlines/British Airways through their antitrust immunity alliance.