Aircraft pilots are reporting a dramatic increase in drone sightings to the Federal Aviation Administration, with the number on pace to quadruple for the year, increasing concerns of a potentially dangerous collision.

On Sunday, four airline crews reported seeing drones while approaching Newark Liberty International Airport in New Jersey at 2,000 to 3,000 feet in the air. All landed safely without taking evasive action.

Pilots from a variety of aircraft reported 650 drone sightings this year through Aug. 9, compared with 238 sightings in all of 2014, the FAA announced Thursday.

FAA: Drone sightings on pace to quadruple this year