Organizers called off the event because of unsafe air quality from nearby wildfires.
Families traveled from across the region to see 1,200 drones recreate characters and scenes from the popular series. Doors opened at 7:15 p.m., but attendees received an email around 8 p.m. announcing that the 9:15 p.m. show would not go on as planned.
"We're all Harry Potter fans. We love Harry Potter, so for this to happen, it's very disappointing," said Montanna Gallardo of Atco, N.J.
Jaylyn Cortes of Vineland said she felt upset.
"I feel bad for my family. I feel bad for me," she added.
Some attendees said they drove hours to reach Chester, only to turn around without seeing the show.
"I'm just frustrated because my wife wanted to go so bad," said Lance Wood of Enola. "I brought my three kids down here, drove over 2 hours. Now it's going to be two hours back. Turnpike fees, gas fees - all that stuff in addition to spending $410 to be here."
The event was organized by Fever and Nova Sky Stories.
Jeremy Sutherland, a senior project manager with Fever, said the team is working to accommodate affected customers.
"We're so, so sorry for guests who came out," Sutherland said. "We know it's a commitment of time and effort to come to the show. We hope they will join us again this weekend."
Many attendees said they cannot return on Friday or Sunday and felt organizers should have alerted guests earlier in the day.
"You should have handled it better," Cortes said.
Sutherland acknowledged issues with communication.
"We apologize for the sequence of how they were notified today and there was miscommunication along the way," he said. "We are reviewing what happened to make sure in the future guests are getting those notifications far in advance."