That's probably something a software developer / tech inclined person would know. Then again, they might assume the app is clever enough to roughly geo-locate you via IP address, and it would kinda make sense as even just knowing the town or state someone is in significantly narrows down the likely list of airports.

But even that uncertainty aside, tech folk are not the primary target audience for this app. The general flying public are. I'm not sure all of this would be immediately obvious to them. And hitting yes to a dialog that sounds as if it's asking for permission to track your every movement sounds kinda scary to me...