In reply to Removed User:
Modern smartphones do not use the mobile RF circuitry for GPS. Therefore, GPS works perfectly well in airplane mode.
If you are using mobile data for mapping, then, yes, airplane mode would stop that. The answer is to use an app that supports caching or downloading of mapping data.
The advantage of airplane mode is that it will significantly increase battery life. My little Moto E2 used only about half its charge for fairly long days walking the TMB.
As for mapping sources, the OpenStreetMap series are very good. It includes maps specific for cycling.