** Shares of U.S. airlines trend lower for second day as global oil prices jump on Middle East conflict escalation

** United Airlines UAL.O, Delta Air Lines DAL.N, American Airlines AAL.O and Southwest Airlines LUV.Ndown between 3% and 5% in early trading hours

** Oil prices have surged roughly 30% so far this year amid conflict, threatening to lift jet fuel costs and squeeze airline profits

** Carriers monitoring fuel price spikes, passengers scrambling to find flights out of the mideast as major Gulf hubs remain closed

** Including session moves, Dow Jones U.S. airlines index .DJUSAR down 9.4% YTD

(Reporting by Aatreyee Dasgupta)

((Aatreyee.Dasgupta@thomsonreuters.com))