The contract now is expected to be rebid, giving Boeing a second shot at the potential $100-billion pact. If the Air Force sticks to its original criteria, Boeing's 767 has a good chance of winning, says Loren Thompson, chief operating officer of the Lexington Institute, a think tank in Arlington, Va. But if the Air Force writes its size preference into new bid requirements, Northrop-Airbus has the edge. Analysts say it's unlikely Boeing would try to rebid using its 777, which is too big and isn't certified as a tanker.