Moving air traffic controllers means retraining them on the quirks of a new facility, and the process can take years.

The Federal Aviation Administration (FAA) on Tuesday defended moving Newark Liberty International Airport’s airspace control to Philadelphia in a statement released in the wake of recent turmoil

The recent chronic delays and cancellations at New Jersey's largest airport have highlighted the shortage of air traffic controllers and the aging equipment they use, which President Donald Trump's administration wants to replace.

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.

Newark Liberty has also been hit by runway construction, equipment outages and air-traffic-control staffing shortages that prompted urgent calls from lawmakers for investigations and new funding.

Transportation Secretary Sean Duffy says a new software update prevented a third radar outage over the last two weeks at New Jersey's busy Newark airport when a telecommunications line failed again over the weekend.

Transportation Secretary Sean Duffy plans to reduce the number of flights in and out of Newark Liberty International Airport for the "next several weeks."

The Federal Aviation Administration said on Monday it will propose flight cuts at Newark Liberty International Airport, citing air traffic controller staffing, runway construction and equipment issues.