Airline websites typically offer detailed lists of banned, restricted or dangerous goods. But it is difficult to keep up with the marketplace — as with this year’s hot-selling virtual reality headsets. More than six million of them have been shipped in 2016, according to SuperData, a market research firm.

Virtual reality gives users a total visual and auditory experience for games and movies. But wearing the goggles and ear-covering headphones can make users oblivious to their surroundings. This is why some airlines have begun prohibiting their use during taxi, takeoff and landing.

“If you are switching off your own situational awareness, you are increasing the risk of injury to yourself if there is an evacuation,” said Jonathan Jasper, also known as JJ, manager of cabin safety for the International Air Transport Association, an airline trade group.

“The guidance across the airlines is they won’t allow them” during those portions of the trip, Mr. Jasper said of the headsets. “They need their passengers to be aware of what is going on.”

Mr. Jasper gets together every six weeks or so with the safety representatives of 17 airlines to analyze the risks and hazards of new technology and consider whether restrictions are necessary.

“The job of an airline is not to upset passengers before they board,” Mr. Jasper said. But airlines feel a need to be vigilant about the things passengers carry with them onto planes.

A flight attendant for a large United States carrier said she was startled recently when she saw that two passengers had attached a small device to a window with a suction cup. The attendant thought it looked like a bomb.