The Federal Aviation Administration is investigating four incidents in three days in New York and New Jersey where pilots reported seeing drones near their planes.

Three drone sightings happened within three days at New York’s John F. Kennedy International Airport. The pilots of Delta, JetBlue, and Shuttle America flights all radioed into air traffic control to report what they saw.

As a result, the Department of Homeland Security has issued a warning that drones could be used by terrorists.

“The rising trend in UAS incidents within the National Airspace System will continue, as UAS gain wider appeal with recreational users and commercial applications,” the statement reads. “While many of these encounters are not malicious in nature, they underscore potential security vulnerabilities – that could be used by adversaries to leverage UAS as part of an attack.”

On Sunday, August 2, the Shuttle America crew reported a drone near the plane’s left side as it was landing, according to the Federal Aviation Administration (FAA). Two incidents occurred on Friday, July 31. JetBlue reported a drone passed just below the plane’s nose as it was preparing to land, and later in the day Delta, flying in an area popular among drone enthusiasts, spotted a drone below its left wing.

In a separate incident on August 2 reported by NJ.com, “a pilot of a Piper PA28 said he had to make a turn in order to avoid a drone while flying 25 miles northwest of Sewell Airport in Washington Township.”

Current rules don’t allow drones within five miles of an airport, unless you first notify the airport operator and control tower, and they must stay below 400 feet. However, as Mario Mairena, senior government relations manager for the group, tells NJ.com, the current federal rules for drones are “simply common sense guidelines” that unfortunately many “enthusiasts are not taking the time to understand.”

“It’s very, very concerning because having drones at JFK or any major airport was illegal even before the latest drone laws came into effect,” CNN aviation analyst Mary Schiavo says. “What is happening now is there are some stiff prosecutions being handed out – including jail time – for lawbreakers. As the people get the word, they won’t do such idiotic things anymore.”

Thankfully, all four of the aforementioned planes landed safely. However, the FAA says it gets a couple of reports every day from pilots who spot drones.

Todd Curtis, founder of AirSafe.com and a former airline safety engineer at Boeing, says “about the worse thing that could happen is that a drone would strike an aircraft and the question is would the impact of the strike be powerful enough to cause significant damage to the aircraft? The answer is: it depends.”

Smaller drones might not cause a threat, but as Curtis points out, current FAA rules allow recreational users to fly drones that weigh up to 55 pounds. “If someone wants to do something crazy, illegal or stupid” they will, Curtis says.

Education of Regulation: What’s the Answer?

As a result of the increasing number of drones being spotted near planes, Senator Dianne Feinstein (D-Calif.) introduced the Consumer Drone Safety Act that looks to shore up safety features on consumer drones and the federal laws that govern their operation.