So far, I've always formatted my SD cards be inserting into the Mavic Air and using the remote/phone.  Can I format on a PC or MAC?  The reason I ask is that there seems to be several folders created on the root drive, with the Mavic Air using the DCIM folder for movies and stills.  If I format on my MacBook, there will be no folders.

Hello. I appreciate your time inquiring about this information to us. If it's the SD card you are referring to format in the PC or Mac, yes you can.

Yes you can without issue and in fact everytime I copy down the media I format using my PC before putting back in AC.  

I am with Sparks, do the same always