Question about DJI Mavic Pro

It is no problem to fly with a mobile phone without a SIM card. However, you need to make sure that you connect your phone to the drone and the internet at the same time to check for updates. Another thing to be aware of is that there is a map in the app that just won't land without a data connection. This was not a problem for me when I flew with the iPad mini without a SIM card. Otherwise it works without further ado.

You can also fly the drone without a mobile phone, just with the controller. I don't know if you can fly it without a sim card, but you can fly it while the phone is in flight mode, which is about the same.