I can’t think of a sector more vulnerable to soaring oil prices than the airlines. Every dollar increase in the price of a barrel of jet fuel adds more than $1.3 million to the daily operating expenses of the U.S. airlines industry. 

Continental Airlines Inc. (CAL) said it would forgo a merger with UAL Corp.’s (UAUA) United Airlines unit, while all-business-class carrier Eos Airlines Inc. ceased operations after filing for bankruptcy protection.

When Skybus Airlines shut down operations and declared bankruptcy over the weekend, it became the third carrier in the span of a week to close its doors.