United Airlines has reached a "resolution" with the owners of a small French bulldog puppy that died during a flight after a cabin attendant ordered it stowed in an overhead bin in March, the carrier said on Thursday.

"We are deeply sorry for this tragic accident and have worked with the Robledo family to reach a resolution," the carrier said in a statement.

United did not disclose how much it would pay the family of the dog, Kokito, in the settlement.

The March incident touched off fresh backlash against the carrier that has made headlines in recent years for various customer service failures.

Social media users at the time called for a boycott of the airline, and two U.S. senators introduced to Congress the "Welfare of Our Furry Friends Act", or "WOOFF" bill, that would impose civil fines for stowing animals in a plane's overhead.

Figures from the U.S. Transportation Department showing that out of 24 animals that died on U.S. carriers last year, 18 were on United flights, were cited by lawmakers as evidence of United's animal problem.

United has implemented new rules for its pet transport service, including barring certain breeds that are known to die during flights at higher rates than others.

The carrier has also said it would begin issuing brightly colored bag tags to passengers traveling with in-cabin pets to help flight attendants easily identify the animals.