In December 2016, a winter weather event disrupted fleet operations, causing Frontier to delay or cancel up to 70% of their flights during the peak of the crisis, many without any advance notice. On the weekend of December 17, the storm caused major delays at Frontier's Denver hub, and the effects of the storm were felt throughout the fleet. Flights were delayed or canceled at airports across the country, as in some cases, planes were ready to depart, but there were no rested flight crews available to service the flight. The head of Frontier's pilot's union issued a statement criticizing the companies' handling of the event, comparing the airline to a "house of cards". Frontier received over 30,000 refund requests for canceled flights resulting from the event.
Frontier Miles is the frequent-flyer program for Frontier Airlines, replacing the EarlyReturns program, which existed from 2003 to 2018. Frontier Miles can be earned by flying Frontier Airlines, using the Frontier Airlines World MasterCard, or by spending at partner hotels, car rental chains, cruises, and merchants. Frontier Miles can be redeemed for flights, magazine subscriptions, and car rentals. Since February 2019, hotel stays are also part of the redemption options.
^ For comparison, fleet ages as of 2018: Southwest, 10.7 years; JetBlue, 9.7 years; Spirit, 5.4 years; WestJet, 9.7 years; Volaris, 4.3 years, Allegiant, 17 years, VivaAerobús, 5.2 years; Sun Country, 14.4 years. Information from Airfleets.net: Southwest, JetBlue, Spirit, WestJet, Volaris, Allegiant, VivaAerobús, Sun Country. (listed airlines from List of largest airlines in North America)
In 2014, Frontier announced it would be transitioning into an ultra-low cost carrier. Frontier will also cut several flights and jobs at their Denver hub and transition them to different markets. On January 16, 2015 Frontier announced that it will close both its Denver and Milwaukee call centers, laying off 1,300 employees and outsourcing the jobs to call center company, Sitel, which operates a large call center for Frontier in Las Cruces, New Mexico. As part of its transition to an ultra-low-cost airline, Frontier Airlines joined Spirit and Allegiant in June 2015 in removing its toll-free telephone number for customer service.