NEW YORK (CNNMoney.com ) - With a deadline looming for the nation's No. 2 airline on the line, Delta Air Line pilots union tried to step up pressure on management by taking another step to prepare for a strike Friday.

On Friday, the Air Line Pilots Association unit at Delta union told its members to clean out their work and personal gear from their lockers.

Management and the union have been locked in discussions on another round of wage concessions as an arbitration panel weighs whether the Atlanta-based airline can dump its union contract. A decision from that panel is due by April 15.

On Tuesday, Delta pilots voted overwhelmingly to authorize a strike. The union says it will strike if the contract is voided by management, although the details of when and where a strike will take place has not been announced.

Even if Delta management wins the right to get rid of the Delta pilots contract, it is not clear when it would take that step. But if it does and a strike results, many airline experts say it could be an end of the airline that has operated under bankruptcy court protections since September.

But many experts still believe a strike is unlikely, even after Tuesday's vote.

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For a look at the growing dispute between Delta and its pilots, click here.

For a look at the improved economic outlook for the airline industry as a whole, click here.