American Airlines produced a record profit of $530 million in its third quarter – an improvement of $420 million over the same period last year.

Revenue was up 6.2% to $6.8 billion in the period, another quarterly record.

The figures come as American and US Airways “vigorously defend” a lawsuit filed by the Department of Justice seeking to block their planned merger.

The two carriers continue to move forward with developing a merger integration plan.

The airlines have vowed to fight the challenge and a trial is scheduled for next month before a federal court in Washington.

American is in the process of restructuring out of bankruptcy protection after two years and hopes to gain clearance at the same time as concluding the tie-up with US Airways.

Tom Horton, chairman, president and chief executive of parent company AMR, said: “We are pleased to report our highest quarterly net profit in American’s history, excluding reorganisation and special items, thanks to the hard work of the entire American team.

“Continued execution on our product, network and alliance strategy, combined with cost efficiencies from restructuring and fleet renewal, creates strong momentum towards our planned merger with US Airways.

“And we are especially pleased to set aside $59 million this quarter in expectation of making our first profit-sharing payout since 2001 to our people who have done so much to put American back on top.”