Officials there said a staffing shortage was to blame for delays Sunday of up to three hours and a ground stoppage.

Frontier Flight 3546 declared an emergency due to engine issues, causing JFK delays and a temporary ground stop.

A Frontier Airlines flight had an engine problem while landing at JFK Airport in New York. The FAA stopped flights for safety and bad weather made delays worse. Many travelers faced long waits, but the plane landed safely.

Air traffic controllers are calling out of work in greater numbers—often forcing the Federal Aviation Administration (FAA) to slow traffic at some of the nation’s busiest airports.

Passengers at Newark Liberty International Airport in New Jersey can expect flights to be delayed by an average of 40 minutes, the FAA said.

A federal investigation into “a flight control issue” is underway after at least 15 people, including children, were taken to the hospital following a sudden drop in altitude on a JetBlue flight that forced an emergency landing in Tampa,

A JetBlue flight made an emergency landing after experiencing a drop in altitude, leaving several passengers injured, according to the airline.

American Airlines Flight 6469 made the abrupt return to Omaha Airport late Monday — less than 40 minutes after departing for Los Angeles.