December 11, 2012 - 09:35 AM ET

Delta Air Lines paid Singapore Airlines $360 million for its 49 percent stake in Virgin Atlantic. Delta and Virgin plan to request antitrust immunity from the Department of Transportation to form by the end of next year a "fully integrated" joint venture. "The partnership allows both carriers to offer a greatly expanded network at Heathrow and to overcome slot constraints, which have limited the growth and competitive capability of both airlines," according to a joint announcement. "The two carriers will operate a total of 31 peak-day round-trip flights between the U.K. and North America, 23 of which operate at London-Heathrow." Combined, the carriers would serve nine daily roundtrips between London Heathrow and New York John F. Kennedy International Airport. "Corporate and travel agency customers of both airlines also will benefit from an aligned sales effort on both sides of the Atlantic," according to the carriers, which plan to launch reciprocal frequent flyer benefits and lounge access.