Delta Air Lines said it will buy almost half of Virgin Atlantic for $360 million as it seeks a bigger share of the lucrative New York-to-London travel market. Delta plans to form a joint venture with Virgin Atlantic, where the two airlines would share money from the flights operated under the partnership. In order to coordinate the schedules of the two airlines, they’ll need antitrust approval from U.S. and European regulators. Landing rights at London’s Heathrow Airport are limited.