PSA: Always keep an eye on your electronics on flights. This includes how much heat they’re giving off.
While most airports and airlines regulate lithium-ion batteries from electronics such as laptops and cameras, there are still other portable devices that can be a hazard on flights, and they don’t even need to be old or visibly damaged.
On A flight from Moscow to Volograd, Russia, a battery in a portable phone charger caught fire while plugged into a seat’s power outlet just as passengers were waiting to deplane.
Russian outlet RT reported that the airline, Aeroflot, denies reports of any flames and that the outlet only put out smoke. However, the video obtained by RT and posted to YouTube clearly shows otherwise.
Source: http://www.travelandleisure.com/travel-news/portable-charger-causes-fire-on-flight
