ST. PETERSBURG — So long, MD-80s. Budget airline Allegiant Air has replaced all of their aging planes at St. Pete-Clearwater International Airport with Airbus models as of August, scrapping its current local fleet. Allegiant is the predominant carrier at the airport, flying 382 routes across the country. "Moving to a single fleet-type will create operating efficiencies across our entire operation, from crew training to scheduling," Hilarie Grey, spokesperson for Allegiant, said in an email. Grey said passengers are likely to see "other aircraft types" throughout the transition, however. The move is part of a larger plan to replace the company's MD-80 planes by 2019, which are inefficient in terms of gas mileage and prone to mechanical problems. The average age of the planes is about 26 years. A Tampa Bay Times investigation in October 2016 found that mechanical issues made Allegiant four times more likely to have unscheduled landings than other airlines in 2015. Airbus 320s average about $98 million each, though Allegiant may have negotiated a bulk price. The airline committed in late 2016 to buying 12 Airbus planes. It did not disclose the final price. Allegiant's Las Vegas-basedparent company, Allegiant Travel Co., posted $400 million in revenue for the second quarter of 2017, a 16 percent increase from the same quarter last year. Contact Malena Carollo at [email protected] or (727) 892-2249. Follow @malenacarollo on Twitter.