PURCHASE, N.Y., Jan 25 (Reuters) - Atlas Air, a unit of Atlas Air Worldwide Holdings Inc. (CGO), said on Friday that it had reached a tentative deal with labor leaders over an initial contract for its flight crews. The air freight operator said the deal is still subject to ratification by its flight crew employees, who are represented by the Air Line Pilots Association. Details of the negotiations were not released. Air Cargo flight crews and management have been negotiating the contract deal since April 2000. Atlas Air, which serves both domestic and international markets, employs 621 pilots and flight engineers for its fleet of Boeing 747 aircraft. Atlas Air shares gained 14 cents to $16.65 at the close of Friday trading on the New York Stock Exchange.