[GTP]

Interesting idea. But, in your vision, what would be the main difference between this approach and actually wiping your device, install just some basic apps you need during the travel (e.g. airline's app for the boarding pass and flight info) and then restore from your cloud backup at the end of the flight? Main difference I see is that Apple/Google wouldn't have access to your data, but this only makes sense if you're not using their services to start with.