Delta Air Lines is asking the U.S. Transportation Department (DOT) to disregard US Airways’ request for new Brazil frequencies that become available to U.S. carriers this year and next. Delta in 2011 agreed to transfer some of its Brazil route rights to US Airways as part of their “slot swap” deal at New York LaGuardia and Ronald Reagan Washington National airports.

“It is very important that Delta receive an allocation of frequencies to offset the required transfer to US Airways, which is now American Airlines’ merger partner and will form a combined entity with a massive portfolio of U.S.-Brazil frequencies,” Delta argues.

The carrier wants to add a second daily flight to Sao Paulo from Hartsfield-Jackson Atlanta International Airport and New York John F. Kennedy International Airport late this year, and continue its existing service from Detroit in 2014. Without the award for Detroit service, it adds, those flights might have to cease when, under the slot swap deal, Delta transfers the rights for seven of its Brazil frequencies to US Airways no later than March 2015.

“At the time it was approved by the department, the Delta/US Airways LGA-DCA slot swap and related Brazil frequency transfer was seen as a way to enable new competitive entry by US Airways, which had no Sao Paulo frequencies of its own,” Delta adds in its March 4 application. “Now, however, in the wake of the announced American/US Airways merger, the contractually obligated transfer of Delta’s unrestricted Brazil frequencies would have the unanticipated result of strengthening the dominant combined American/US Airways entity, and weakening Delta, already the smallest player.”

US Airways and American also have applied for the Brazil frequencies, which are becoming available under the U.S.-Brazil aviation agreement that will phase in open skies between the two countries by October 2015. The phased rights include 14 additional weekly frequencies to Sao Paulo that become available for U.S. carriers in October this year and 14 more in October 2014.

US Airways wants seven October 2013 frequencies to “continue without interruption” the Sao Paulo service from Charlotte Douglas International Airport, N.C., that is scheduled to begin in June, using frequencies on short-term lease from another carrier. It wants another seven to begin service to Sao Paulo from Philadelphia International Airport in October 2014.

American wants frequencies to begin daily service to Sao Paulo from Los Angeles International Airport in November and from Chicago’s O’Hare International Airport in November 2014.