Operations at United Airline's massive hub at Newark Liberty International airport have stabilised following a sharp reduction in daily air traffic mandated by the Federal Aviation Administration.

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.

A failed backup telecommunications line led to a 90-second radar and radio outage last month that left air traffic controllers unable to see jetliners heading into Newark airport.After the primary connection that carries radar data into the Philadelphia facility where controllers guide planes into the busy hub failed,

Newark approach lost radar and comms with at least 16 commercial jets. Many circled in oval loops before landing elsewhere. A CNN data analysis reveals the ripple effects from the outage.

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

Delta Air Lines, JetBlue and American Airlines are the top three U.S. carriers at JFK, according to aviation analytics company Cirium. To regain a foothold, United must negotiate with the FAA or acquire slots from one of those three.