The airline had a consistent growth until 2008, but Frontier was forced to file Chapter 11 bankruptcy, due to its credit processing company First Data’s demand for the carriers upfront ticket proceeds during a volatile time in the market. Frontier emerged from bankruptcy with an acquisition from then-partner Republic Airways Holdings who was simultaneously bidding for Midwest Airlines. Republic merged the two airlines in 2011, leaving Frontier as the surviving brand. By 2013, Republic wished to spin off Frontier and made a sale agreement with Indigo Partners, the same investment company that once owned Spirit Airlines. Following the purchase, to no surprise Frontier announced it would transition to an ultra-low-cost carrier. Overhauled as a ULCC, Frontier has ambitious plans to expand its route network and is continuously adding new cities it plans to serve with its $15 billion order from Airbus.

Headquartered in Denver, CO, Frontier Airlines offers around 300 daily flights to 90 destinations across the United States, Canada, Dominican Republic, and Mexico. Frontier maintains its hub at Denver (DEN), but also relies on focus cities in Austin (AUS), Atlanta (ATL), Chicago (ORD), Cincinnati (CVG), Cleveland (CLE), Las Vegas (LAS), Miami (MIA), Orlando (MCO), Philadelphia (PHL), and Raleigh (RDU) to serve approximately 16 million annual passengers.

Frontier’s frequent-flyer program EarlyReturns is one of the few distances based programs left, awarding actual miles flown between airports. However, EarlyReturns mileage balances expire after six months of inactivity; so users need to fly semi-regularly with the airline or actively spend using a no-branded Frontier credit card to keep the account active. Frontier is not a member of any alliance but maintains one code-share agreement with Mexican-based Volaris, making it the world’s first ultra-low-cost carrier partnership.

Similar to Spirit Airlines, Frontier flies a fleet of only Airbus aircraft, with 78 in service and a whopping 195 more on order. Read Less