American Airlines (AA, Dallas/Fort Worth) has pledged to pay USD45 million to settle a consumer antitrust lawsuit in which it, together with the other three largest US-based carriers, was accused of colluding to drive up fares on domestic flights, Bloomberg has reported.

The carrier continues to deny all allegations and has not admitted to any wrongdoing. The deal is yet to be approved by a judge.

"Despite our firm conviction in the appropriateness of our actions, costs to defend against antitrust litigation often run into the tens of millions of dollars. So while it is difficult to agree to a settlement when we believe we were right on the law and the facts, settling this case is a prudent decision for American," spokesman Matt Miller has said.

American has also agreed to produce business records. Three of its current or former employees would also testify about the data and practices under oath.

In January, Southwest Airlines agreed to pay USD15 million to settle the same case. United Airlines and Delta Air Lines are still under litigation. Both carriers deny any wrongdoing. United has pledged to continue defending itself in court.

The lawsuit, filed in its current form in early 2016, alleges that the airlines cooperated to limit capacity despite growing demand and low fuel prices. They also allegedly colluded to keep foreign competitors away from the US domestic market and hindered consumers' capabilities to compare prices.