ST. PETERSBURG, Fla. — Allegiant Airlines is retiring its aging fleet of planes. 

  • Allegiant replaces fleet of MD-80s with Airbus planes
  • Allegiant main carrier at  St. Pete-Clearwater Airport and Sanford Airport
  • Airline now has 70 Airbus planes

Allegiant, which has come under scrutiny in recent years due to problems with its MD-80 fleet, is replacing the older jets with Airbus planes. 

Allegiant is the main carrier at St. Petersburg-Clearwater International Airport and at Sanford International Airport. 

Last week, the airline flew its last MD-80 flight with a plane close to 30 years old. The aging planes, which made up 30 percent of the airline's fleet, were notorious for bad fuel efficiency as well as mechanical issues. 

The airline now has a fleet of more than 70 Airbus planes. 

The MD-80 was the main reason the airline was under the microscope last year when investigations showed the airline was four times more likely to have in-air mechanical problems compared to other carriers. 

The report also came after a 60 Minutes investigation into the airline and incidents such as smoke in the cabins, rapid descents and mid-air engine failures.

Allegiant retired its fleet of MD-80s at St Pete-Clearwater Airport last fall and has now completed its nationwide replacement of the older planes. 

In a statement, Allegiant CEO Maurice Gallagher, Jr said "our decision to move the transition up by a year from 2019 to 2018 has proven to be an excellent one given the higher fuel cost environment."

Allegiant has beat major carriers like American Airlines and Delta Airlines in replacing all of its MD-80s. American plans to stop using its MD-80 planes by sometime next year.