Trippler, with the Web site MyVacationPassport.com, said consumers will benefit in the long run from healthier airlines and, as a result, a more stable transportation system. He said competition should remain strong and fares shouldn't climb much.

Kevin Mitchell, however, said ticket prices would rise significantly and the public can expect service disruptions, repercussions from labor strife and more job insecurity in the airline industry if the carriers merge. He said that if all the deals in discussion come about, there will effectively be three fewer U.S. network airlines in operation.

"Shareholders, advisers and other firms are the big winners here," said Mitchell, chairman of the Business Travel Coalition, an advocacy group. "I would view it, if I'm a business traveler, on the customer service side as many years of unimaginable pain."

Joe Brancatelli, an independent business travel analyst, said consumers already are losers from merger mania — with or without deals being consummated.

"So much management time is being consumed by creating or fighting a merger," said Brancatelli, who runs a Web site for business travelers called joesentme.com. "All that time would have otherwise been spent on plugging holes in the already creaky system."

While discount airlines aren't the focus of merger speculation, combining the larger, so-called legacy carriers could provide an opening for budget carriers such as Southwest Airlines Co., JetBlue Airways Corp. and AirTran Holdings Inc. to push their ticket prices higher as well.

Orlando-based AirTran said Wednesday its $290 million offer for rival Midwest Air Group Inc. was rejected, but it will continue trying to acquire the Milwaukee-based regional carrier.

United, based in Elk Grove Village, Ill., and Continental have many hurdles to clear to make any deal come about.

Regulators could look at the combined airline's added strength in the Northeast as detrimental to competition, with Continental's Newark hub and United's at Washington-Dulles. United already has endured a failed merger with US Airways in 2000 because of regulatory opposition.

United's prickly labor situation also could be problematic after multiple cuts and layoffs in recent years. The carrier's outspoken flight attendants union quickly served notice Wednesday that it has "severe reservations."