Delta Air Lines (DL, Atlanta Hartsfield Jackson) has requested the US Department of Transportation (DOT) revoke back-up authority granted to rival American Airlines (AA, Dallas/Fort Worth) to operate Los Angeles International-Tokyo Haneda flights citing its inactivity.

Late last year, American and Hawaiian Airlines (HA, Honolulu) took Delta to task over its decision to operate its now terminated Seattle Tacoma International-Tokyo Haneda on a seasonal basis. This, they argued, was a gross under-utilization of a coveted slot for the Japanese capital city's most centrally-located airport.

But, while the DOT ultimately found in Delta's favour, it imposed stringent conditions for it to retain the slot; conditions that Delta later declared commercially unsustainable. As such, Delta announced in June that effective October 1, it would relinquish its second Haneda slot. As per the DOT's ruling, the slot subsequently passed to back-up carrier American Airlines which had said it would be prepared to operate daily Los Angeles-Tokyo Haneda return flights using a B777-200(ER) within sixty days of it being awarded the slot.

However, Delta now argues that despite American's original commitment, American has yet to file any schedules for its proposed service let alone sell tickets for it. This, Delta, claims, shows American "has no intention of inaugurating the service as promised". Delta has now requested the DOT to revoke the slot from American Airlines and reavail it to other interested operators.

"Given the strict conditions imposed on Delta, it would be unfair, arbitrary and capricious to allow American to violate the terms of its backup award and retain slots for Los Angeles-Haneda service that it has no intention of operating within the next 60 days. The slots should be immediately returned to the unallocated pool forthwith," Delta argued.

American, in its defense, has blamed the Japanese authorities for the delay in the roll out of the route claiming they have yet to allocate the airline a “commercially viable” slot time. American says it is trying to secure nighttime slots to provide customers with “a reasonable schedule and reasonable connectivity” and, given the circumstances, now hopes to begin Los Angeles-Tokyo Haneda flights by March 27, 2016.

The two carriers have had an acrimonious relationship of late as Delta earlier this year attempted to block Alaska Airlines (AS, Seattle Tacoma International) from transferring its Los Angeles International-México City International route authority to American. Delta also recently cancelled an existing interline ticketing and baggage agreement with American on the grounds that the deal "was no longer mutually beneficial.”