Unable to reach an agreement, American Airlines and Delta will end an interline ticketing accord from tomorrow.
It means passengers must now buy separate tickets and check bags separately with each carrier during a multi city journey.
"We have been unable to come to terms on an agreement with Delta and, as a result, have mutually agreed to end our interline agreement effective September 15," American spokesman Casey Norton.
"From that date, neither airline will offer interline services to each other, including the ability to rebook passengers at discounted rates on the other carrier when flight disruptions occur."
"Interline agreements are common across the industry and they generally include a standard, discounted rate for calculating how much is owed by one carrier to another to use their seats during irregular operations," an American statement said.
"Delta recently decided to go outside of that joint agreement and negotiate an individual agreement with American but we have been unable to come to terms on an agreement."
