American Airlines said in a statement that a "technology issue briefly impacted connectivity" for some systems.
The group is calling on American Airlines to negotiate a new union contract.
American Airlines says pilots aboard one of its flights mistakenly thought someone was trying to breach the cockpit on Monday.
Gate agents will now be asked to use their judgment about whether a bag is too big and needs to be checked -- and if they're not sure, to err on the side of the customer.
The American Airlines jet was going around 154 mph and was nearly airborne when the controller immediately instructed the plane to abort takeoff, according to the FAA.
A stowaway was found dead Sunday in the landing gear of an American Airlines flight that arrived in Charlotte from Europe, according to police.