Change in IP location? If you suddenly jump across the country but your traffic is still coming from a cell provider (so unlikely to be a VPN) Lyft could infer that you've flown, and to which airport.
Alternatively maybe barometer? All modern iPhones have one, but I don't know if apps are allowed to access it in the background (or without location services), and it wouldn't let Lyft tell which airport you were at.
Comments
Change in IP location? If you suddenly jump across the country but your traffic is still coming from a cell provider (so unlikely to be a VPN) Lyft could infer that you've flown, and to which airport.
Alternatively maybe barometer? All modern iPhones have one, but I don't know if apps are allowed to access it in the background (or without location services), and it wouldn't let Lyft tell which airport you were at.