NEW YORK (Reuters) - United Parcel Service Inc. (NYSE:UPS - news), the last remaining customer for the Airbus A380 superjumbo freighter, said on Friday it reached an agreement for Airbus to push back delivery dates of the planes and left open its option to cancel the order outright. ADVERTISEMENT UPS, the world's largest package delivery company, has been rethinking its order for 10 A380 freighters since October, when Airbus announced a third delay on the giant plane due to wiring problems, putting it two years behind schedule. UPS's planes were originally scheduled for delivery between 2009 and 2012. The company...