I have a Mavic Pro drone. Having the included payload of a goTenna mesh does not seem particularly burdensome in calm conditions - and having that ability to bring a relay up to relatively high altitudes could greatly increase long-range reception. There are a bunch of different mounts for drones (and other things) for mounting GoPro cameras. So I put together a little mount so I could attach a relay to the underside of my drone without obstructing the sensors.
The design was intentionally made to be very lightweight - so it’s probably not particularly durable. But for normal flight, it should be fine. This is a first draft and I can tighten up some tolerances and strengthen a few areas - but this is probably “good enough”.
You can find the stl and modify it to fit your needs. It’s available (with more photos) here: https://www.thingiverse.com/thing:4015022