Does anyone know if while travelling overseas without cell coverage and without data, if one can use offline maps in mobile phone from another app like maps.me to fly the drone?

Hello there Mr Marde. Thank you for reaching out and for these inquiry. You will be needing an internet connection when updating your DJI application on your mobile device. It is suggested to put your mobile device on airplane mode while flying it would lessen the interference like receiving calls and text messages while on flight. In addition, since the maps.me is a 3rd party application. I hope that you will get the best recommendation from our fellow DJI co pilots who uses the said application. Thank you.