The disruptions at Newark Liberty International Airport continue with delays and cancellations, after more than 500 flights were impacted Sunday. As of 8:30 a.m. Monday, the airport reported 20 delays and 73 cancellations,

The Federal Aviation Administration said staffing issues, low clouds and construction were hindering traffic at the airport, resulting in average delays of about four hours for some arrivals. Officials recommended travelers check with their airlines to see if their flights were affected.

Hundreds of flights were canceled or delayed at Newark Liberty International Airport over the weekend and again on Monday as shortages of air traffic controllers persists, causing flight disruptions at one of the nation’s busiest airports.