Two major U.S. airlines, Delta and Northwest, have declared bankruptcy, citing high fuel costs as a reason. “Hurricane Katrina was probably the last straw,” said a securities analyst keeping an eye on the proceedings.

Carriers in other countries are also feeling the petroleum pinch: Air China, British Air, and others are increasing the fuel surcharges that pass costs along to customers.

The two U.S. airlines — the nation’s third- and fourth-largest, respectively — will keep plying the friendly skies. But don’t expect extra pretzels.