It's an unusual in-flight issue that's become such a problem, airlines have been forced to come up with strategies to deal with it.
And that issue is passengers who watch porn mid-flight.
Airlines are reporting an increasing number of passengers who watch X-rated content on their personal devices on flights, sometimes in front of children.
Now, in an extraordinary step, major American carrier United Airlines is giving its cabin crew extra training to help stop passengers watching porn on planes.
The airline was forced to invest in the extra training after it briefly made the US National Centre on Sexual Exploitation (NCOSE) 2019 "Dirty Dozen List", which names and shames companies that "facilitate sexual exploitation" in the United States.