By Melissa Garcia

DENVER (CBS4) – Frontier Airlines announced Tuesday that it will begin offering service to 21 new cities from Denver International Airport.

The new destinations include Palm Springs, California; Jackson Hole, Wyoming, and Buffalo, New York.

Management at DIA said more airline competition could lower the cost for passengers to fly. The growth also means the airport will have to make more room, a task that may not come quickly enough.

Adding to its current destination count of 50-cities from DIA, Frontier’s new routes will all be offered by the summer of 2018. As of the announcement, the low-cost airline was already offering service to eight of the new cities at an introductory sale price of as low as $39.

“I think it’s an awesome idea,” said Patrick Clark, a Frontier passenger. “I mean, the airlines need more flights, more options.”

The company’s ambitious 15 to 20 percent annual growth plan includes buying more planes, hiring more workers and increasing its customer base.

CBS4’s Melissa Garcia interviews Patrick Heck, Chief Commercial Officer at Denver International Airport. (credit: CBS)

“Substantial traffic growth, passenger growth, and activity in airports all across the United States,” added Jimmy Dempsey, CFO of Frontier Airlines.

The 40 percent increase in Frontier destinations from the Mile High City means that DIA will have to expand its capacity. The airport will open six new gates by the end of 2017 and is working to come up with a long-term solution.

“It’s no secret that we are busting at the seams right now with all the growth that we’ve seen from Frontier, from our other carriers here,” said Patrick Heck, Chief Commercial Officer at Denver International Airport. “And so we are really pursuing some growth and some expansion of all of our concourses.”

Some experts in the industry were predicting successful growth by the airline.

(credit: CBS)

James Simmons, Aviation Professor with Metropolitan State University of Denver, said that despite the carrier’s widely known recent problems in on-time performance, customer satisfaction and labor, its ultra low-cost business model is proving to be a popular and profitable one.

“Finding ways to keep costs low, I think they’re going to be able to do this,” Simmons told CBS4’s Melissa Garcia.

Simmons said that the private company is on track to become a public corporation by the end of 2017, fueling speculation of an upcoming merger.

“With possibly another low-cost carrier. My speculation is that they may be gearing up towards a possible merger with Spirit Airlines,” Simmons said.

Melissa Garcia has been reporting for CBS4 News since March 2014. Find her bio here, follow her on Twitter @MelissaGarciaTV, or send your story idea to mkgarcia@cbs.com.