Many years ago, I noticed I could browse the Google Play Store on a flight WiFi without paying for it. No images would load and no apps would download, but I could browse through app listings and read reviews.
Probably not. I bet something in Android didn't work properly until they whitelisted some Google domains — for example, maybe it didn't detect the Internet connection when the user paid for it, or maybe something on the entertainment tablets broke (I don't know if they usually run Android or something else).
This seems likely. ~6 years ago on a Delta flight I noticed that I could use Google and view cached pages without paying for WiFi. I managed to catch up on the news on my flight…
Would this be related to DNS?