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,[41] 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.[42] 

On November 15, 2017 Frontier Airlines announced a $15 billion order for 134 additional A320neo family aircraft. The order, slightly revised under new owner Indigo, consists of 100 A320neo and 34 A321neo. The order also includes the conversion of the remaining A319neo to A320neo.[80] With this order, Frontier Airlines fleet has industry-leading fuel efficiency. The fleet is also one of the most modern and young, particularly in comparison to other low-cost carriers,[nt 1] at an average age of 5 years as of 2018.[81]
Say for example there are two hotels side by side. One meets all the requirements of the Diamond classification, pool, valet etc etc. The other may have vastly better quality rooms, best furnishings, best of everything but does not have a pool. If that was your hotel, even though anyone can clearly see that it's better than the hotel next door, would you feel it's fair it won't meet the Two Diamond standards?