By Kyle Peterson

CHICAGO (Reuters) - The proposed merger of Delta Air Lines Inc (DAL.N: Quote, Profile, Research) and Northwest Airlines Corp NWA.N is likely to spur other carriers to go after the cost savings and global brand recognition required to survive amid soaring fuel prices and a weak U.S. economy.

If the long-awaited consolidation wave were, in fact, at hand, the airlines most likely to follow suit would be UAL Corp's (UAUA.O: Quote, Profile, Research) United Airlines and Continental Airlines Inc (CAL.N: Quote, Profile, Research), which reportedly have been in talks for months.

Continental said on Tuesday that it would review strategic alternatives. But pilots of both companies said they would not back a merger unless they approved of the terms.

With industry conditions increasingly hostile, and Delta potentially improving its competitive position, other legacy carriers might find themselves in desperate need of a merger.

"There will be a great deal more pressure on United and Continental to look at a combination facing the threat of a large Delta/Northwest merger," said Jim Feltman, aviation consultant for Mesirow Financial Consulting on Tuesday. "It's almost compelling as opposed to desirable."

The industry has been battered by hefty fuel bills, directly linked to the price of crude oil, which notched a record high near $114 a barrel on Tuesday.

Those cost pressures combined with a weakening U.S. economy have put airlines in an increasingly awkward position that could lead to another steep downturn like the one triggered by the 2001 terror attacks on the United States.

In Tuesday trading, Delta shares fell 12.6 percent to $9.16 and Northwest shares closed down 8.4 percent at $10.28, both on the New York Stock Exchange.