Organized labor groups planned a rally on Thursday July 12 in front of the Enterprise Rent-A-Car near Logan Airport, the Boston Globe reports.

Groups led by IUE/CWA Local 201 and the Greater Boston Labor Council are upset that the rental agency hired a subcontractor to run its Logan operations after 30 employees began efforts to unionize.

Enterprise spokesperson Christy Conrad said Enterprise hired a staffing service to improve operations at the Logan center. Conrad said the service, which manages 20 other Enterprise centers, is committed to giving job interviews to all current Enterprise workers, according to the Boston Globe report.

The National Labor Relations Board is reviewing a complaint by workers that Enterprise retaliated against them for pursuing unionization by outsourcing their jobs.

Meanwhile, the Greater Boston Labor Council is warning the Massachusetts Port Authority, which oversees Logan International Airport, not to allow Enterprise to operate on airport land if the labor dispute isn’t resolved, according to the Boston Herald.

Senators Edward Kennedy and John Kerry signed a letter in support of the movement, according to a report on WCVB, Boston’s ABC affiliate.

Enterprise denies any wrongdoing.