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.
On September 9, 2014, Frontier introduced an updated livery, as part of a rebranding that saw the spokesanimals' roles increase. The new livery reintroduced a green "FRONTIER" typeface to the fuselage, featuring the stylized "F" designed by Saul Bass for the original Frontier in 1978. Each aircraft features the name of the animal featured on its tail near the nose of the aircraft for easier identification. Currently about twenty five aircraft in the Frontier fleet feature the new livery.
On January 11, 2007, Frontier Airlines signed an 11-year service agreement with Republic Airlines. Under the agreement, Republic was to operate 17, 76-seat Embraer 170 aircraft for the former Frontier JetExpress operations. At the time the contract was canceled in April 2008, Republic Airlines operated 11 aircraft for Frontier Airlines, with the remaining six aircraft expected to join the fleet by December 2008. With the integration of Republic aircraft, the 'JetExpress' denotation was removed. Subsequent to the cessation of Horizon's services for Frontier in December 2007, all flights operated by Republic were sold and marketed as "Frontier Airlines, operated by Republic Airlines." The first market created specifically for the Embraer 170 was Louisville, Kentucky, which began on April 1, 2007. Service to Louisville was suspended in August 2008 but restarted in April 2010.
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.
In July 2017, Frontier announced 21 new cities and 84 new routes. These cities include Buffalo, Charleston, S.C., Pensacola, Jackson Hole, Palm Springs, San Jose, Reno, Little Rock, and Tulsa. Destinations that saw a significant bump-up in new service include Austin, Cincinnati, Long Island/Islip, N.Y., Miami, Orlando, Providence, San Antonio, and Tampa.
jetBlue's first major advertising campaign incorporated phrases like "Unbelievable" and "We like you, too". Full-page newspaper advertisements boasted low fares, new aircraft, leather seats, spacious legroom, and a customer-service-oriented staff committed to "bringing humanity back to air travel". With a goal of raising the bar for in-flight experience, jetBlue became the first airline to offer all passengers personalized in-flight entertainment. In April 2000, flat-screen monitors installed in every seatback allow customers live access to over 20 DirecTV channels at no additional cost.
In April 2013, Frontier introduced a modified version of that livery, keeping the iconic animals on aircraft tails, but dropping its former slogan and replacing "FRONTIER" with "FLYFRONTIER.COM", the company's website, in support of new marketing that focused heavily on the airline's web presence. This livery was only painted on a few newly delivered aircraft. Aircraft in the older livery received "FLYFRONTIER.COM" titles on engine nacelles.
Various consumer rights organizations and activists called for the creation of a government mandated “Bill of Rights” to protect air travelers from future experiences similar to the one previously described. On February 20, 2007, jetBlue released an apologetic response to the events that had taken place less than a week before with the creation of their Customer Bill of Rights, which offers financial reciprocation if a customer's flight is delayed or cancelled.
JetBlue Technology Ventures (JTV)  is a wholly owned subsidiary of JetBlue that was established in February 2016. JTV is the venture capital arm of JetBlue that invests in and partners with early-stage startups in the travel, hospitality, and transportation space. Its mission is to improve the end-to-end experience of travelers everywhere. As of November 2018, JTV has invested in 21 startups, including hybrid planes, machine learning algorithms, and ground transportation. Investments range in size from $250,000 to $1 million.