The Air Line Pilots Association has asked its United members to approve a dues increase to help pay for a potential dispute over seniority in the event of a merger, Crain's Chicago Business reported.

Seniority is said to be the major issue of contention in talks on a merger between Delta Air Lines Inc. (NYSE:DAL) and Northwest Airlines Corp. (NYSE:NWA), the newspaper said. Negotiations stalled last week as pilots, who had given preliminary approval to a merger, dug in their heels over seniority issues.

The ALPA asked United pilots for an additional 0.5 percent of their wages, Crain's said, but only in the event an announcement is made of a merger involving United.