Airbus could lose its largest and most prominent A350 customer, Qatar Airways, because of its indecision over the aircraft’s configuration and the likelihood that it will adopt an all-new design. The Qatari flag carrier – currently an all-Airbus operator – last year became the lead A350 customer when it announced at the Paris air show that it intended to order 60 of the twinjets for delivery from 2010 after an evaluation that included the rival Boeing 787. Although the airline later began to firm up the deal by signing a letter of intent for the 60 aircraft, it has held...