American Airlines ended a years-long dispute with its mechanics in late March with the ratification of a new contract.
And earlier this month, the two sides also ended a dispute over whether the mechanic unions should have to pay sanctions.
Previously, American Airlines Group Inc. sought sanctions against the Association, a joint venture of the International Association of Machinists and Aerospace Workers and the Transport Workers Union that together represent American's mechanics, for the financial damage the the carrier said it incurred during an alleged orchestrated mechanic slowdown last year.
American, the largest carrier at Phoenix Sky Harbor International Airport, had a dismal operational performance last summer which it said stemmed from the mechanic slowdown and the lack of 737 Max jets in its fleet.
