The FAA implemented a ground delay program to control how many flights land at once in the reduced-visibility conditions. As a result, the average arriving flight is being delayed by 67 minutes from 2 p.m. to 11 p.m.
Air quality alerts in place as smoke hangs over region | Live updates
"Whereas a ground stop halts all traffic, the ground delay will still allow flights to get in; it will just space it out a little bit more," said Heather Redfern, public affairs manager for Philadelphia International Airport.
Travelers departing and arriving at the airport reported concerns about both flight schedules and air quality as smoke lingered over the region.
Michael Lem, who was traveling through Philadelphia from Houston, said he was relieved to be indoors while monitoring potential delays.
"You're worried about your air quality and breathing all that stuff in, so not so excited about it," Lem said.
The delay program follows similar FAA measures Thursday, when Philadelphia International Airport recorded 365 delays and 12 cancellations. Airport officials said pilots reported low visibility and ash on their windshields.
A Code Purple air quality alert was issued in Philadelphia because of wildfire smoke from Canada that has lingered over the region. Public health officials urged people to remain indoors when possible.
Redfern said delays affecting arriving flights could also impact departures.
"There could be a ripple effect for departing flights from PHL as is always the case when there's weather or some sort of delay," she said.
Some travelers said they planned ahead for possible disruptions.
"Fingers crossed," said Latasha Lambert of Baltimore.
Lambert said she built extra time into her travel plans.
"The good thing is, we're a day early for our flight so if it is delayed then if it is delayed it won't cause us to miss our cruise," she said.
Other passengers said safety concerns outweighed frustration over longer waits.
"It's really bad in Michigan. People are wiping ash off of their vehicles. I saw a lot of emergency room visits and things like that, so I'm going to take it seriously," said Sara, a traveler from Flint, Michigan.
The ground delay program was scheduled to remain in effect until 11 p.m. at Philadelphia International Airport.
Airport officials recommended that travelers check with their airlines for the latest flight information before traveling.