When I fly, I like to cache a map of the region I fly over on my phone, particularly the airport region at the destination. Then, you can hold your phone to the window for a few minutes and get a GPS fix, even if in airplane mode, because as you say GPS is purely passive.
Then you can follow along nicely where you are, at the resolution you want. (Sure, many airlines have moving maps, but they're not as good as Apple maps or Google maps.)
Once I was flying in the middle section of economy, on a flight without in-flight WiFi, and accidentally opened Google Maps on my phone. I was shocked to find it managed to see enough GPS satellites to provide a lock, which matched the map in the seat back in front of me.
Terrorism isn’t the reason you can’t use cell networks during a flight. Early on it was ostensibly interference concerns but those are not a real problem (if they were they wouldn’t let you carry cell phones onto a plane).
At this point it’s an explicit request from the cell phone companies to not have a plane with 200 people ripping through their cell networks with association attempts that are most likely going to fail and then immediately become stale.
When I fly, I like to cache a map of the region I fly over on my phone, particularly the airport region at the destination. Then, you can hold your phone to the window for a few minutes and get a GPS fix, even if in airplane mode, because as you say GPS is purely passive.
Then you can follow along nicely where you are, at the resolution you want. (Sure, many airlines have moving maps, but they're not as good as Apple maps or Google maps.)