MIAMI -

American Airlines grounded almost half of its fleet of Boeing 757s Thursday night because of seats becoming loose mid-flight.

More than 20 flights in and out of Miami International Airport were cancelled after American announced 48 planes would be further inspected.

American released the following statement on Thursday:

Working with the FAA, American Airlines is taking additional steps to prevent seats from becoming dislodged on some of our Boeing 757 aircraft. After further analysis by our engineering team, the company is taking additional preventative steps to enhance the locking mechanism features used to secure the seats to the aircraft floor.

“American has instructed mechanics to pay particular attention to the seat lock plunger mechanism that secures the seat to the aircraft floor. Mechanics have begun taking steps necessary to ensure that no seat can become dislodged from its track. The work is expected to be completed after the 48 affected aircraft land at their next destination.

“Some select flights may be delayed or canceled in order to complete this work. We expect this work will be completed by Saturday, Oct 6.  We apologize to our customers for any inconvenience this may cause with their travel plans. The safety of our customers and people as well as the reliability of our fleet, is always of utmost priority to American.

“We have confidence in our highly skilled maintenance and engineering teams as well our contract maintenance providers who have worked on all of the 757 aircraft involved.

We continue to work closely with the FAA to resolve this matter. – American Airlines spokeswoman Andrea Huguely

The FAA, which is investigating, also issued a statement, saying: "The FAA is aware of American's decision to conduct further inspections on certain Boeing 757s and concurs with this step. Our safety investigation continues and we'll take additional action as appropriate."