After making a codeshare agreement with Lufthansa that went into effect in 2010, jetBlue transitioned to the Sabre reservation system used by Lufthansa,[107] enabling the airlines to sell tickets on each other's flights, transfer luggage and passengers between the two carriers, and combine frequent flyer programs,.[108] By making use of JetBlue's North America routes as a feeder network, the agreement put Lufthansa in a position to operate quasi-hubs in New York–JFK and Boston Logan.
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.[citation needed]
Frontier Airlines was the launch customer of the Airbus A318. Between 2003 and 2007, they took delivery of 11 of the type. However, retirement of the type already began in 2010 and was completed by autumn 2013. All of Frontier's A318 were not resold, but parted out for scrap. At the time of scrapping, the five youngest examples had spent less than two and a half years in active service, while the oldest two were just over ten years old.[82]
In May 2005, the airline's holding company, Allegiant Travel, completed a private equity placement worth $39.5 million that was funded by the investment firms of ComVest and Irelandia II.[16] In November 2006, Allegiant filed a registration statement with the Securities and Exchange Commission in anticipation of a planned initial public offering of its Common Stock. It raised $94.5 million in equity capital with 5.75 million shares worth $18 each.[16] It began trading on the NASDAQ Stock Market under the ticker symbol "ALGT" in December 2006.[16]
During the last few days of June and the first few days of July 2015, jetBlue began charging for bags in certain booking classes, leaving Southwest Airlines the only major U.S. carrier to not charge for bags. For the classes in which bag check fees are charged (generally the lowest class of fares offered; jetBlue offers 3 classes of fares), the cost is $20 for the first bag and $35 for the second, which is the lowest in the United States besides Frontier Airlines with similar prices.[62]
We arrived at the airport at 5:15 for our 7:15 flight. After two delays we received a text message from the company that the flight had been canceled. 35 minutes later an employee finally came out to announce the cancellation. As we started asking questions like “will we get our money back” or “do you have any more flights going out we can get on” each time a piece of paper was picked up and shaken in our faces and were told to read the paper just like everyone else. Worst service ever!!!!!! We were all states away from home with no where to go and no help from frontier. And our refund could be expected within two weeks. All I could think of is how I hoped everyone there could find funds to purchase another ticket to where they were going. Because last minute tickets are crazy expensive. I will never fly frontier again!!!! They gave me a $100 voucher off my next flight with them but I’ll never use it!!!
In 2014, Frontier announced it would be transitioning into an ultra-low cost carrier.[47] 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.[48] 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.[49]

The company had charter contracts with Caesars Entertainment to ferry customers to Caesars casino properties through Reno-Tahoe International Airport, Laughlin/Bullhead International Airport and Tunica Municipal Airport.[48] These contracts ended in December 2012 when Caesars Entertainment signed a new contract with Republic Airways to provide the charter service to Caesars properties in Atlantic City, New Jersey, Tunica, Mississippi and Laughlin, Nevada.[49] 

As part of its plan to stay competitive in reaction to the entry of Southwest Airlines into Denver, the company underwent a reorganization early in 2006. On April 3, 2006, Frontier created Frontier Airlines Holdings (FRNT), a holding company incorporated in Delaware to take advantage of favorable tax laws in that state. The corporate headquarters did not leave Colorado.[21] 

jetBlue previously had its headquarters at 80–02 Kew Gardens Road,[80] and then in the Forest Hills Tower, both in Forest Hills, Queens, New York City,[81][80] 6 miles (9.7 km) from the current office in Long Island City.[82] In 2001 the airline had announced that it wanted to take 74,000 square feet (6,900 m2) of space in the Forest Hills Tower, and by December 2002 announced that it planned to increase its leased space.
On September 9, 2014, Frontier introduced an updated livery,[86] 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.
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