The Transportation Department said Wednesday that “in some cases,” wheelchair users were injured, but it did not give a number.

American said it has made significant investments to improve the handling of wheelchairs. The airline will be credited $25 million, or half of its civil penalty, for those investments and compensation paid to affected passengers, according to a consent order.

The incidents raised by the Transportation Department occurred between 2019 and 2023.

The investigation was prompted in part by three formal complaints the Paralyzed Veterans of America filed against American.

Investigators also seized on video of an incident at Miami International Airport last year. Workers slid a wheelchair down a baggage ramp. It crashed into the bottom of the chute, flipped over and skittered across the concrete.

Transportation Secretary Pete Buttigieg said American Airlines “appeared to be one of the worst offenders,” but the problems that investigators found “are not confined to one airline.” He said the department is conducting similar investigations into other airlines, but he would not name them.

“The era of tolerating poor treatment of wheelchair users on airplanes is over,” Buttigieg declared to reporters.

From 2019 through 2023, American mishandled more than 10,760 wheelchairs and mobility scooters, according to Transportation Department figures. Only Southwest Airlines, at more than 11,100, had more incidents. Spirit Airlines had the highest percentage of errors in several of the years, according to the department.

American said it has invested more than $175 million this year on infrastructure, training and other steps to improve the travel experience for people with disabilities.

American said it has cut its rate of mishandling wheelchairs and power scooters by more than 20%, and fewer than one in every 1,000 customers who ask for wheelchair assistance wind up complaining to the airline.

The punishment for American is far more severe than the Transportation Department meted out to other airlines that it determined had violated laws protecting travelers with disabilities. The previous record penalty was $2 million against United Airlines in 2016, which was reduced to $700,000 after United got credit for compensating passengers and other spending.

Department officials said the size of the fine against American reflected the large number of incidents, which included damaging wheelchairs or taking too long to return them to passengers after flights.

Federal regulations require airlines to return wheelchairs and scooters to customers quickly and undamaged after flights, and to help passengers with disabilities get around airports and get on and off planes. Airlines are required to pay for repairs or replacement of damaged wheelchairs, but advocates say that can still leave users without a suitable way to get around for weeks.