At times Monday evening, as few as three air traffic controllers per hour were lined up to monitor via radar the planes flying into and out of the airport, the Federal Aviation Administration said.

The award-winning new Terminal A may be the pride of Newark Liberty International Airport. But behind the scenes, the technology that’s keeping the planes in the sky is frighteningly out of date. Some of it relies on floppy discs and used parts sourced from eBay, federal officials said this week.