Delta Air Lines CEO Richard Anderson told employees on Aug. 26 that while DL supports the proposed transatlantic joint venture among American Airlines, British Airways and Iberia "in principle," it will advocate that "AA and BA need to give up enough slots and gates so that everybody has unfettered access to Heathrow."

The employee hotline message was cited by The Dallas Morning News.

BA CEO Willie Walsh has gone on record saying that carrier will refuse to surrender slots at LHR.

An AA spokesperson told The Dallas Morning News that AA does "not believe surrendering slots is necessary given the number of new entrants with service to Heathrow, which clearly demonstrates that slots are available through the open market and intra-alliance transfers."

DL flies nonstop to LHR from New York JFK, Atlanta and Los Angeles.