I know that an external bluetooth microphone is an option but the audio quality may suffer with delays, bitrate, etc. However, what if you could capture audio using your smartphone instead with something like the Rode SmartLav+ that connects directly to the 3.5mm headphone jack? On iPhone, you can use any number of external microphones using the lightning to camera adapter. It would be awesome to capture the external audio and video from the 360fly without having to separately sync them in post.
Anyways, just shooting for the stars with this suggestion!