About 250 unionized pilots that had struck cargo airline ABX Air Inc. last Tuesday returned to work the following evening after a federal district court judge in Ohio ruled that a staffing dispute with management must be resolved through arbitration and other provisions of their collective bargaining agreement.

The one-day walkout by Local 1224 of the Teamsters union's Airline Professionals Association resulted in ABX, a unit of Wilmington, Ohio-based Air Transport Services Group Inc. (ATSG), cancelling 75 flights on Tuesday. ABX operates 45 flights a day for German express giant DHL Express, and along with another ATSG unit operates 35 daily flights for Seattle-based e-tailer Amazon.com Inc.

The dispute that led to the ABX pilot walkout centers on how much the pilots should be paid for extra flying, especially as the peak holiday shipping season commences. The pilots have argued that ABX deliberately understaffed its pilot rolls during the past two years, resulting in the pilots flying thousands of emergency assignments for which they have not been properly compensated.

The company said the battle constitutes a "minor dispute" under the Railway Labor Act (RLA), the federal law governing airline labor relations, and should be settled through arbitration or ongoing negotiations. Judge Timothy S. Black agreed with management's interpretation.

"I am pleased that the court continues to recognize the value to all parties from continuing to work out remaining differences in negotiations and through arbitration," ABX Air President John Starkovich said Wednesday in a statement. "We intend to resume those discussions at the appropriate time and place in order to find solutions that are in the best interests of our customers, shareholders, and employees."

In a statement Wednesday, Rick Ziebarth, chairman of the local's executive council, said the members disagreed with the judge's decision on grounds that the company had violated the Act's "status quo" provisions by not fairly compensating the pilots for so many emergency assignments. "Rather than spend more time in court, what we'd really like is for ABX to stop the 'emergency' assignments and take real steps to hire and retain the number of skilled pilots we need to keep up with our customers," Ziebarth said.

According to the pilots, ABX refused to recall crews that were furloughed after DHL Express ceased domestic U.S. operations in January 2009. The company then chose to hire new pilots and set their pay at the bottom of the wage scale, rather than pay more to recall experienced DHL pilots, the union argued. ABX compounded the problem by waiting too long to hire pilots, and then hiring too few of them, according to the union.