Denver-based Frontier Airlines announced Tuesday 16 new flight routes coming next year.

The ultra-low fare airline is adding two of those routes to Denver International Airport. The new additions will return service to Tucson, Ariz. and Reno, Nev., Frontier said in a news release.

Frontier paused service between Denver and the southwestern cities in 2021. The airline halts service when demand isn’t high enough, Frontier Corporate Communications Manager Rob Harris told The Denver Gazette in an email, and resumes them once “market conditions have improved.”

The route between Denver and Tucson will begin March 3 and flights to Reno will begin March 7. Service will run three times a week, according to Frontier.

“With our return to Tucson, Ariz., Reno, Nev., and Antigua and Barbuda, and with expanded service from cities coast to coast, consumers can continue to look to Frontier as their ultra-low cost carrier of choice,” said Josh Flyr, Frontier’s vice president of network and operations design, in a release.

Frontier also expanded service to Antigua and Barbuda with flights from San Juan, Puerto Rico.

The added routes from Denver start at $19 if purchased before 11:59 p.m. on Nov. 25.