Overhead, the whine and drone of plane engines rumbled on, with fuselages seeming to get so low that pedestrians could see the landing gear and make out a carrier’s name. One local resident, Rob Lenhard, 24, said he could understand why someone would resort to laser pointing. “Honestly, I’ve gotten drunk a couple times and thought about doing it myself,” he said. “I’m not going to lie.” He does not own a laser, Mr. Lenhard added.

Image A police photo of a laser found in a Bronx home. Credit... New York Police Department

To federal and local authorities, though, “this is no joke,” said Samuel M. Goldwasser, a laser expert and a former professor of engineering at the University of Pennsylvania. It is only a matter of time, he said, before a pilot, perhaps a “weekend pilot” in a single-engine plane, feels a sudden blast of laser light, panics and loses control.

While the federal Food and Drug Administration regulates laser devices, it is easy to buy hand-held lasers that exceed “the legal limit of 5 milliwatts by a factor of a hundred or more,” Dr. Goldwasser said. He said the laser the police accused Mr. Egan of using was more powerful than the law allowed and was “definitely not a presentation pointer.”

“But there is a danger to aviation, even with low-powered lasers, which can result in distraction and temporary flash-blindness,” said Dr. Goldwasser, who writes the online guide Sam’s Laser F.A.Q. “It all depends on ‘How powerful is the laser? How far away is the aircraft?’ To what extent the person holding the laser can sustain contact with the cockpit.”

He added: “Unlike in ‘Star Wars,’ the beam does expand.”

Across the country, reports of lasers being pointed at commercial aircraft rose to 3,690 in 2013 from 283 in 2003, the F.A.A. said, though no such instances have been cited as a factor in a crash.

Last year, the New York office of the Federal Bureau of Investigation began a national campaign to deter “laser strikes” since the number of episodes in the New York area had nearly doubled, to 99 in 2013 from 52 in 2010; it offered up to $10,000 as a reward for information on people pointing lasers at planes. The number of episodes in the New York area fell to 71 for last year, said J. Peter Donald, an F.B.I. spokesman, but there have already been 31 this year, he said.