Travelers heading to Newark Airport via AirTrain are fuming on social media about a sudden, unexplained slowdown in service as the holiday weekend gets underway.

People took to Twitter to complain that AirTrains were not working and feared they would miss their flights.

"Insane scene at #EWR Airtrain," tweeted one woman. "Hundreds will miss flights... no train/bus, ppl fighting, employees hiding."

She later told NBC 4 New York in an email that her husband had taken the train from Newark Penn Station to take the AirTrain, and got caught in chaos as people waited for AirTrains that never showed up.

"There were a lot of people yelling and pushing as new trains from Penn Station arrived, only flooding the waiting area even more," she wrote. "One bus arrived but that clearly couldn't handle the volume and everyone was fighting to get on. Employers on walkie-talkies hid in corners and didn't communicate anything to the masses trying to get out."

"Many people were freaking out as they knew there would be no way they'd make their flights given the extensive delays," she said.

Another NBC 4 New York viewer headed to Terminal A from NJ Transit tweeted, "Madness at the air train. Not working. 1 bus every 10 mins... Hundreds waiting and will miss flights."

He said he was lucky to get on the bus and make his flight: "Not sure about others."

Another traveler tweeted, "Um @NY_NJairports #EWR, really with the airtram down and no frequent buses to take people to terminals??? What are you doing?"

Travelers seemed equally frustrated with the lack of communication from Port Authority, saying they couldn't find any updates online and there were no announcements.

The Port Authority only said unusually high passenger volume and ongoing construction in the area delayed service.

The Newark AirTrain connects with NJ Transit and the rail lines that run on the Northeast Corridor and North Jersey Coast Line.