Some delegates to the Democratic National Convention say they will fly into other airports rather than risk crossing any picket line set up by airport workers at the Philadelphia International Airport.
The workers - who clean airplane interiors, handle baggage at the curb, direct passengers through airport lines and help people in wheelchairs - are employed by subcontractors who work for the major airlines.
On Tuesday, nearly 500 of them cast ballots saying they would be willing to strike during the convention, although no strike date has been set.
Spokeswomen for both the airport and the airport's largest airline, American Airlines, say any protests by the workers will not disrupt customer service.
A labor union, SEIU Local 32BJ, is trying to organize the workers into a union, but has not, despite several years of effort. Former U.S. Labor Secretary Robert Reich and other delegates have signed a petition supporting the workers.
"I am a newly elected member to the DNC from California and a delegate to the Democratic National Convention in Philly and will be flying into New York City and driving into Philadelphia so as not to cross a picket line," delegate Susie Shannon wrote in an email.