The deck has worked fine for me in multiple countries without issue on wifi.

The WiFi thing is just to make sure you go online before you go on the plane and put your deck into offline mode. Then means a game like GTA can log in to the rockstar servers and once it does you can go into offline mode, put the deck in sleep mode and board the plane and play it on the plane.

It mainly has to do with online games. On planes I tend to play emulated games to get max battery life.

I sometimes use my phones hotspot to pit the deck into offline mode in I’m playing in the airport waiting to board