DENVER -- About 80 Frontier Airlines employees and passengers made one final, very public push to save the Denver-based carrier.

Dozens of people rallied at the Denver City and County Building Tuesday then marched down the 16th Street Mall.

"We would hate to see Frontier disappear," said Kate McLaughry. "We love it."

Monday is the deadline for companies to place binding bids to acquire Frontier, which filed for bankruptcy in April 2008.

Republic Airways Holdings has offered to acquire Frontier for $108.7 million, saying it plans to operate Frontier as usual. Frontier would be intact as a wholly owned subsidiary.

However, Dallas-based Southwest Airlines has submitted a nonbinding proposal of $113.6 million, proposing integrating Frontier into Southwest.

University of Denver business professor Mac Clouse told 7NEWS that money is not the only factor to be considered.

"If it's close, you can make the argument that it's based on intangibles," he said.