According to the New York Post, a blackout on April 28 for air traffic controllers overseeing Newark led to many workers taking trauma leave, exacerbating its staff shortage. In addition, a Newark Airport runway is closed for “rehabilitation work” leaving the airport with only one functioning runway.

At one point, the FAA had targeted 77 total arrivals and departures at Newark each hour, but at the start of construction on April 15 they requested airlines cut that down to 70 total during the day and 62 during specific hours in the late afternoons and evenings.

The New Jersey airport, which has faced radar problems and major delays, is scrambling to bring in more air traffic controllers and complete construction.