United, American and JetBlue flights will be impacted if the strike resumes.
The union represents wheelchair attendants, baggage handlers, customer service agents, and cabin cleaners.
The workers at PHL were to be joined by others at Newark Liberty, LaGuardia, John F. Kennedy and Denver global airports, whose strikes were also suspended after beginning at 9 p.m. Tuesday.
Headquartered in Manhattan, Local 32 BJ of SEIU, the Service Employees International Union, has 163,000 members, primarily in property service jobs, also known as janitors, along the East Coast.
The strike is also being held at several other airports and impacted operations in the East on Wednesday morning.
The labor dispute is between the workers and a private company, PrimeFlight Aviation Services.
Travel was also affected at John F. Kennedy International Airport in NY, as well as airports in Philadelphia and Washington because of walkouts.
Some workers from AirServ, PrimeFlight and G2 are striking.
KUSA reports as many as 150 behind the scenes employees were planning to walk off their jobs Wednesday at 11:30 a.m.to protest what they call health and safety issues as well as low pay. The strike would continue for at least three days.