Spirit Airlines has filed plans with the government to go public, hoping to sell some $300 million in shares later this year (the filing is here).

This marks a milestone of sorts. We haven't seen an airline go public in the U.S. since 2007, when Gulfstream International (GIA) hit the market, Bloomberg reports. By the way, GIA shares are now a whopping 68 cents.

Spirit gained notoriety this year when it started charging fees for carry-on bags. Yep, you read that right. A Spirit passenger will pay $45 per bag at the boarding gate, or $30 per bag when paying in advance (bags that can fit under a seat, however, get on for free).

The airline justified the fees by saying that its fares were already super-cheap. Spirit's average base fair is around $85.

Spirit has $264 million in debt, Bloomberg reported, and some of the IPO proceeds will likely go to pay that down. The company said it will retain $150 million in proceeds.

The airline mainly flies between Florida, the Caribbean and Latin America. In its filing, Spirit says it has been able to cut its operating costs significantly over the last few years. It uses an all-Airbus fleet with "high-density seating," it says, and uses less fuel per available seat mile than any other U.S. airline.

Spirit sees lots of opportunities to expand in the Caribbean and Latin American markets, and wants to grow by increasing routes and aircraft capacity.