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 expanded service to the Caribbean, including to St. Maarten and Puerto Plata commencing January 10, 2008. With these additional destinations, jetBlue serves a total of twelve Caribbean/Atlantic destinations including Aruba; Barbados; Bermuda; Cancún; Nassau; Aguadilla; Ponce; San Juan, Puerto Rico; Santiago; and Santo Domingo, Dominican Republic.
On April 10, 2008, Frontier filed for Chapter 11 bankruptcy in reaction to the intent of its credit card processor, First Data, to withhold significant proceeds from ticket sales.[better source needed] First Data decided that it would withhold 100% of the carrier's proceeds from ticket sales beginning May 1. According to Frontier's press release, "This change in practice would have represented a material change to our cash forecasts and business plan. Unchecked, it would have put severe restraints on Frontier's liquidity..." Its operation continued uninterrupted, though, as Chapter 11 bankruptcy protected the corporation's assets and allowed restructuring to ensure long-term viability. After months of losses, Frontier Airlines reported that they made their first profit during the month of November 2008, reporting US$2.9 million in net income for the month.
On October 22, 2008, jetBlue opened its new primary hub at John F. Kennedy International Airport (JFK), Terminal 5, or simply T5. The mostly new terminal, costing approximately $800 million, partially encircles the historic TWA Flight Center, the former Trans World Airlines terminal designed by Eero Saarinen, which remains closed. According to the plan, passengers will eventually be able to check in for flights in the landmark building, then transfer to the new structure via the original passenger departing-arrival tubes from Saarinen's original terminal and its 1969 addition by Roche-Dinkeloo.
In an effort to focus on regional contract flights for major carriers, Republic Airways Holdings announced in January 2012 its intention to sell or spin off Frontier. On January 26, 2012, Republic Airways Holdings appointed former US Airways and Gate Gourmet CEO David Siegel as President and CEO of Frontier Airlines. Republic also added new senior officers for Frontier's finance and commercial team, among other changes in the executive leadership team. Siegel and other Frontier executives moved to Denver where Frontier is headquartered in order to facilitate management of all aspects of Frontier during its separation process from Republic and continue its transformation into an ultra-low-cost carrier.
Frontier Airlines (F9) is a Denver-based low-cost carrier. The carrier flies to about 65 destinations in the United States, Costa Rica, the Dominican Republic, Jamaica and Mexico. Its fleet of planes each feature a single Economy Class cabin. However, passengers can upgrade to Select Seating, which is located toward the front of the plane, or Stretch Seating, which features more legroom. Frontier's hub is based at Denver International Airport (DEN). An additional eight airports have been designated as focus cities. The airline has a codeshare agreement with Great Lakes Airlines.
In July 2013, Frontier started service from New Castle Airport near Wilmington, Delaware to five destinations, which Frontier markets as Wilmington/Philadelphia. Again, this airport had no commercial service prior to Frontier's entry. New Castle Airport lies roughly 30 miles southwest of Philadelphia International Airport and 75 miles northeast of Baltimore–Washington International Airport.
As Republic Airways Holdings was in the process of bidding to acquire Frontier in 2009, it was also in the process of acquiring Milwaukee-based Midwest Airlines. Through the fall and winter of 2009, Republic operated its two new acquisitions as separate brands. However, to improve efficiency by better matching aircraft capacity to route demand, Republic began to intermix the fleets of the two airlines, swapping a portion of its higher-capacity planes from Frontier with its smaller-capacity planes from Midwest and vice versa. However, the move caused some confusion amongst the public, as the two brands did not offer the same amenities and did not match the amenities mentioned on the airfare. As a result, in the Spring of 2010, Frontier and Midwest Airlines announced that their brands would merge, with Frontier being the surviving brand. This was a merger of brands only—no Midwest Airlines aircraft was ever operated by Frontier, as by this time, all Midwest Airlines flights were operated on its behalf by other Republic Airways Holdings subsidiaries.
On December 13, 2007, jetBlue and Germany-based Lufthansa announced jetBlue's intent to sell 19% of jetBlue to Lufthansa, pending approval from US regulators. Following the acquisition, Lufthansa stated they plan to seek operational cooperation with jetBlue. Lufthansa plans to offer connections to JetBlue flights in Boston, New York (JFK), and Orlando International Airport (no longer a connection).
On October 13, 2009, the airline unveiled a modification to its livery in commemoration of the upcoming 10th anniversary of the airline in February 2010. Besides a new tail design, the revised livery includes larger "billboard" titles extending down over the passenger windows at the front of the aircraft. The logo word 'jetBlue' will no longer be silver and blue but now a dark, navy blue.
That's why I decided to use it again for our Rosarito getaway on Labor Day weekend. Found a less than fancy hotel at an amazing price of $53, taxes and breakfast included. It was perfect for our needs, as we were only staying one night, and sleep only for a few hours at that. I ignored all the bad reviews of the hotel being dirty and unsafe, but I never imagined that so much worse awaited us. When we arrived, they told us that they were full and that there was no record of our reservation to begin with. How did that even happen? And if the hotel had been full since Friday, how did it allow me to do the reservation on Thursday? I couldn't reach them in Mexico. By the time I was able to talk to someone we were already in the United States and unable to take an alternative room. We only had one night, I didn't want to waste it looking for hotels when we had already checked two others at a way higher price. The only reason we went out there is for the amazing advertised price, the price I thought we had locked in through a reservation. But no way was I going to fall in that game of taking a more expensive room out of desperation. We just left. Drove back all the way to L.A.
In 2007, jetBlue was also facing reliability problems with its Embraer 190 fleet. For a couple of months, jetBlue contracted ExpressJet to operate four Embraer 145 regional jets on behalf of jetBlue. While this was going on two E-190 aircraft at a time were sent to an Embraer maintenance facility in Nashville, Tennessee. ExpressJet operated routes between Boston Logan and Buffalo, New York and Washington Dulles, and between New York–JFK and Columbus, Ohio (has terminated) and Richmond, Virginia.
In May 2017, Allegiant Air took delivery of its first brand-new A320. Allegiant took delivery of ten new A320s in 2017 and is scheduled to accept two in 2018. All new aircraft will be painted in Allegiant's new livery at the time it is delivered. Older Airbus aircraft will be repainted during their C-checks. The new Airbus aircraft will have fuel-efficient sharklets. The new A320s seat 186 passengers, an increase of the 177 seats that are found in the rest of the Allegiant A320 fleet. To fit the additional nine seats, Allegiant opted for the Airbus Space-Flex V2 Lavatory. 
Although it does not fly to Canada, Allegiant advertises extensively there and flies from about a dozen small airports near the Canada–US border. Many of its customers at airports such as Bellingham, Washington (BLI), Niagara Falls, New York (IAG), Ogdensburg, New York (OGS), Grand Forks, North Dakota (GFK) and Plattsburgh, New York (PBG) are Canadians, who can save money by flying from U.S. airports.
In July 2016, jetBlue announced commercial flights from the United States to Cuba will commence in late August. On August 31, 2016, JetBlue Flight 387 from Fort Lauderdale–Hollywood International Airport to Abel Santamaría Airport, in Santa Clara, became the first scheduled commercial flight between the United States and Cuba in 55 years. Only charter flights were allowed under previous rules, which required that passengers had to arrive more than 4 hours before the scheduled departure and often endure long lines for documentation checks, late flight arrivals, and pay high baggage fees.
In October 2013, Republic Airways Holdings entered into an agreement with private equity firm Indigo Partners to sell Frontier Airlines for approximately $145 million. According to Indigo, the transaction would further Frontier's evolution into an ultra-low-cost carrier. In December 2013, Indigo Partners LLC, through an affiliate, completed the purchase of Frontier Airlines from Republic Airways Holdings. The airline's headquarters will remain in Denver. Republic Airways Holdings subsidiary Republic Airlines no longer flies Embraer 190 aircraft on behalf of Frontier, as of January 1, 2014.
In August 2017, Allegiant announced a new base would be established at the Indianapolis International Airport. The base began operations in early 2018. In February 2018, Allegiant also announced a new base would be established at the Destin–Fort Walton Beach Airport. In June 2018, Allegiant added another base at McGhee Tyson Airport in Knoxville, Tennessee. In January 2019, Allegiant announced they would be adding another base at Gerald R. Ford International Airport in Grand Rapids, Michigan.
Allegiant Air has been closely monitored by the FAA due to many emergency landings and aborted takeoffs. ABC interviewed a former Allegiant mechanic, who said "Dedicated steps were not being performed with maintenance manuals or even with general practices, before an aircraft is released." Many of these incidents had involved Allegiant's aging MD-80 aircraft, which as of November 2018 have been replaced by newer Airbus A320 family aircraft. 46 of the 86 aircraft have made emergency landings, all of which were on MD-80s. The average age of Allegiant's MD-80 fleet was 29 years compared to less than 13 years for its Airbus fleet.
In October 2005, JetBlue's quarterly profit had plunged from US$8.1 million to $2.7 million largely due to rising fuel costs. Operational issues, fuel prices, and low fares, JetBlue's hallmark, were bringing its financial performance down. In addition, with higher costs related to the airline's numerous amenities, JetBlue was becoming less competitive.
The initial JetExpress partnership with Mesa ended in January 2004, when Horizon Air was selected to operate the routes. Horizon utilized slightly larger CRJ-700 regional jet aircraft on these routes. In August 2006, Frontier and Horizon ended their partnership. While Frontier was generally pleased with Horizon's operation, the carrier decided that it needed to revisit the agreement and find a provider with additional regional jets to grow the operation. The last of the CRJ-700's was returned to the Horizon Air fleet on November 30, 2007.