Frontier Airlines has filed a registration statement with the U.S. Securities and Exchange Commission to sell shares to the public. The Denver-based carrier wants to launch an initial public offering (IPO) as soon as the current quarter.

Frontier is owned by private-equity firm Indigo Partners, and operates nearly 300 daily flights in the United States, Mexico, and the Dominican Republic.

The carrier, whose business motto is "low fares done right," offers inexpensive base fares but charges extra for everything else. Frontier has been expanding and will fly to 18 nonstop destinations from Philadelphia International Airport this summer.

The last U.S. airline to go public was Virgin America is 2014. Virgin was acquired by Alaska Airlines last year. In 2011, Spirit Airlines went public.