Why can’t I activate my 03 air unit from mobile. Twice I have driven two hours to fly on an air unit I already activated only to have 2 of 4 drones need to be reactivated. One the I landed changed battery and then the air unit said needs activation. If I could do it from mobile I would not have been half stuck out there on a drone trip.

Hi, there. You can connect the air unit to a computer using the USB-C cable， and run DJI Assistant 2（Consumer Drones Series）for activation or Firmware updating.
You can also refer to the teaching video on our official website. https://www.dji.com/uk/o3-air-unit/video