PENN TWP — What seemed to be a near flawless campaign rally Saturday evening turned into something very different at the end.

About 15,0000 supporters of President Donald Trump leaving the Pittsburgh-Butler Regional Airport in Penn Township — all at once — created a walking traffic jam on West Airport Road, authorities said.

The exiting mass of humanity combined with other vehicle traffic headed back into the airport delayed the arrival of shuttle buses and left rally-goers out in the dark and the cold for an uncomfortable amount of time.

“People were highly disgruntled because they were waiting,” said Butler County Sheriff Mike Slupe.

A “Chinese fire drill” is how Penn Township police Cpl. Jack Ripper described it.

“The buses were getting jammed up,” Ripper said. “There were people (in vehicles) that were trying to get into the airport to get their equipment out and blocking the buses and people were walking on the road not letting buses through.

“It was a mess at the beginning.”

The rally ended shortly after 7:30 p.m., and before long the huge crowd began streaming out.

Slupe said the other vehicles on the road along with the massive departing crowd stalled buses from picking up the rally-goers from the staging area on the middle of West Airport Road.

The Trump campaign leased 40 buses from three companies to be used for shuttle service between the airport and three remote parking sites on Hicks and Powell roads in Penn Township and at Butler County Community College in Butler Township.

The shuttle plan worked well busing people into the airport for the event because it was over a period of hours.

“But they let them out of the rally at one time,” Ripper said. And, as it happened, he added, “This was one of the coldest nights of the year and I'm sure a lot of people were freezing.”

Slupe said the bus drivers were doing the best they could under the circumstances.

“Most of the people were very, very understanding,” he said. But, he added, “I appreciate the people that were upset. I get it. But they didn't come at one time, they left at one time.”

Al Lindsay, chairman of the Butler County Republican Committee, and his wife, the committee's internal vice chairman, were two in the crowd stuck for a while in the temperature that dipped into the low 40s.

“The problem was,” Lindsay said, “there was confusion. There was no one directing people. You have (thousands of people) standing there. You should load here, you should load there. No one knew. That was the problem.”

The last of the buses came and went around 10 p.m.