The chief executives and their representatives from seven low-cost airlines sought support from the Bush administration yesterday in their campaign to derail a proposed marketing alliance by Delta Air Lines, Northwest Airlines and Continental Airlines.

The chief executives from Air Tran Airways, America West Airlines, Frontier Airlines, JetBlue Airways, Midwest Express and Spirit Airlines joined with executives from Southwest Airlines in an hour-long meeting with R. Glenn Hubbard, chairman of the White House Council of Economic Advisers.

"We're concerned about this purposed alliance and its ramifications for competition in near and long term," said America West chief executive W. Douglas Parker. "We wanted to communicate that message to as many decision makers as possible."

The group has lobbied several government officials during the past several months. In November, the executives met with Transportation Secretary Norman Y. Mineta.

Representatives for Mineta and Hubbard declined to comment on the meetings.

Delta, Northwest and Continental, the nation's third-, fourth- and fifth-largest airlines, applied in August to share passengers and sell tickets on one another's flights. The "code-sharing" agreement would enable the three carriers to expand their route systems by flying passengers to those destinations where they individually do not fly. The agreement would also enable travelers to earn and redeem frequent-flier miles between the three airlines.

The possible alliance sparked an outcry from smaller airlines and consumer advocates, who warned the pact would stifle airline competition.

Parker, along with the other executives, said they were also concerned that the three airlines would influence major corporate clients and make it difficult for low-cost carriers to gain access to markets where the three carriers dominate.

The Transportation Department is expected to rule on the alliance by Monday. Delta lobbyist Scott Yohe said the three-way alliance was patterned after the United Airlines-US Airways alliance, which was approved by the government. Yohe said the three-way alliance was not anti-competitive because the carriers would continue to compete with one another.

"We are not going to be in a monolithic situation where customers aren't able to chose between the three airlines," Yohe said.