PARIS (Reuters) - A majority of Air France pilots backed a deal reached in October to develop the company's low-cost operations in France, the airline said on Wednesday. Some 53 percent of Air France pilots approved the agreement, reaching 60 percent for members of the majority union SNPL, Air France said in a statement. The agreement followed a two-week strike that the airline has said is likely to cost 500 million euros ($616 million) . Pilots forced Air France's Franco-Dutch parent Air France-KLM to ditch plans to expand its low-cost brand, Transavia, in Europe, fearing that the project would erode their own pay and conditions. To date, more than 200 Air France pilots have volunteered to fill the 72 positions available at Transavia France, it said. Under the deal these pilots would retain their Air France contracts but sign with Transavia France a "detachment" contract setting pay and holiday terms during their time at Transavia. Air France has said it wanted to speed up the development of Transavia, which it believes is vital for the well-being of the company at a time when myriad low-cost airlines are taking root across Europe. Transavia France aims to operate 21 aircraft in the Summer 2015 compared with 16 in Summer 2014, and has a target of operating 37 Boeing 737 by 2019. (Corrects first paragraph to say October, not September, and changes third paragraph to say cost is estimated at 500 million euros instead of "over 280 million euros") (Reporting by Dominique Vidalon; Editing John Irish and Andrew Callus)