The pilot unions at Delta Air Lines and Northwest Airlines Thursday begin a series of arbitration hearings to determine how to combine their seniority lists for the airlines’ proposed merger.

The first arbitration session runs from Thursday through Sunday in Marina del Rey, Calif.

Subsequent hearings are scheduled for Oct. 20-24 and Nov. 15-17 in the Washington, D.C. and Los Angeles areas. The unions expect a decision by Nov. 20, and Delta and Northwest expect to close the merger by the end of the year, pending approval from the U.S. Department of Justice.

Both sides agreed to a three-member arbitration panel that includes Richard Bloch, Fred Horowitz and Dana Eischen. Bloch, who is the chair of the panel, said “everyone is hopeful that this can be done in as non-litigious a manner as possible.”

Committees from the pilot unions, who are separate units of the Air Line Pilots Association, have been in negotiations on seniority integration while preparing for the arbitration hearings.

The Delta pilots union has been “preparing a sound, strong case,” according to Delta pilots union spokeswoman Kelly Regus. “We remain open to a negotiated solution even during the arbitration process.”

Bloch said he would “vigorously endorse” a negotiated solution.

After US Airways’ 2005 merger with America West, the pilots submitted to arbitration to integrate their seniority lists, but some pilots disagreed with the arbitrated ruling. The pilots voted to replace their union with one seeking to throw out the arbitrated seniority ruling.

The Delta and Northwest pilot unions agreed to the binding arbitration process earlier this year, and in August ratified a new labor contract to take effect with the close of the merger.