United Airlines has matched the bonus offers of Delta and American by offering United MileagePlus members 15,000 bonus miles for a first transatlantic roundtrip flight, 35,000 bonus miles for a second flight and 50,000 bonus miles for a third and subsequent flights. The offer is only valid in first, business or full-fare coach (F, A, J, C, D, Z, P, Y or B) flights between the U.S. and London on United Airlines for travel through Jan. 31, 2013. There is no limit to the number of bonus miles you can earn and registration is required before travel at http://insideflyerus.wpengine.com/link/?7474