Power banks are allowed on planes, but only in the cabin, and only up to a certain size.
Cabin bag only
Spare lithium batteries, including power banks, must never go in checked bags. Keep them in your cabin bag or pocket.
Reading the Wh rating
Up to 100 Wh is fine; 100 to 160 Wh needs the airline’s approval; over 160 Wh is not allowed. A 20,000 mAh power bank at 3.7 V is about 74 Wh.
