The U.S. Department of Transportation has granted final approval of antitrust immunity to the joint venture of Delta Air Lines, Air France-KLM and Virgin Atlantic, allowing the carriers to combine their two separate agreements with Delta into a single joint venture. The antitrust immunity in the previous agreement, which included Alitalia, will expire after six months, according to DOT. In its final order, DOT said that the carriers could petition to extend the that immunity if they come to a commercial agreement with Alitalia before that six-month period elapses.