Boeing warned on Wednesday that orders for its commercial aircraft could be cancelled or deferred as airlines struggled to cope with the high cost of fuel.

“Clearly, economic conditions are tough for many of our commercial customers, with oil prices putting significant pressure on them to restructure their businesses,” said Jim McNerney, chief executive. “We are concerned about the impact of energy prices on our customers, and we do expect that we could have more deferrals and some cancellations.”