rigorousintuition.ca

Commercial pilots are accustomed to sharing the sky with birds or, more recently, drones, but on Sunday two pilots reported a novel sighting at 3,000 feet approaching Los Angeles International Airport: a man flying a jetpack.

“Tower, American 1997 — we just passed a guy in a jetpack,” the pilot of American Airlines Flight 1997 from Philadelphia told air traffic control, about 6:35 p.m. Sunday. The exchange was captured and posted by LiveATC.net, which shares live and archived recordings of air-traffic-control radio transmissions.

“Were they off to your left side or right side?” the controller asked. The pilot said the person was 300 yards to the plane’s left, and about 30 seconds later, another pilot said he had also seen the man pass by. The controller, after asking the pilot of JetBlue Flight 23 to keep a lookout, added, “Only in L.A.”

Now both the F.B.I. and the Federal Aviation Administration are investigating.

Jetpacks have long been portrayed as futuristic vehicles in comic books and spy movies, but not much headway has been made in making the technology safe and available for recreational or commercial use.

The main issue is fuel efficiency — most jetpacks are not equipped to fly for more than a few minutes, making it difficult for them to get very high. The devices are mostly popular among enthusiasts or used as tourist attractions for thrill seekers who want to experience a few minutes of flight, typically over open fields or water.

Glenn Martin, an inventor from New Zealand, tried to develop a jetpack that would be practical for commercial use and could reach higher altitudes. The device was named one of the best inventions of 2010 by Time, which reported that the jetpack could theoretically take a person up to 8,000 feet and hold 30 minutes’ worth of fuel.

But when a New York Times reporter tried it in 2008, Mr. Martin said his team had not taken the device higher than six feet. He speculated that “if you can fly it at three feet, you can fly it at 3,000.” Ten years later, the company appears to be defunct.