U.S. airlines, largely unprofitable and saddled with poor debt ratings, are enjoying surprising success raising money at a time when other companies are struggling amid the credit crunch.

Airlines are building cash as a bulwark against global recession and losses on fuel-price hedging efforts. They are selling stock, selling and leasing back planes, refinancing assets and tapping the debt markets for secured loans. They are also turning to a collection of vendors, suppliers and business partners that stand to make money if the airlines just stay aloft.

Wall Street showed more signs of stability Tuesday after Washington’s latest lifeline to the auto industry bolstered hopes that the government would keep taking whatever steps were necessary to cut short the recession.

Investors were comforted after GMAC, the financing arm of the General Motors Corporation, received $5 billion of financing. The Treasury Department said late Monday that it would provide the money to GMAC Financial Services from the $700 billion bank rescue program.