Las Vegas-based budget carrierAllegiant Air has a rather interesting fleet history, having initially flown rear-engined McDonnell Douglas narrowbody twinjets from the DC-9 and MD-80 families in its early years. Since then, it has grown to rely heavily on single-aisle Airbus jets from what is now known as the A320ceo (‘Current Engine Option’) family, but, as it looks to the future, it has deployed a new strategy.