A great shot can easily be ruined when you or the crew come into camera view or the UAV shadow passes through the shot.
It may seem cool to see yourself or the aircraft but in most cases it is a distracting element that takes away from the end product.
While some of this can be removed in post, it is much better to try and avoid it when possible with some proper planning of you location and flight paths.
Take into account the sun angles and the position of various structures, where their shadows will fall, where talent needs to be positioned, and where the flight path needs to be to get the shot required, and the flight crew’s required line of site to do the shot safely. It may require reworking initial shot setups to make for a clear end to end shot or finding alternative takeoff/landing zones to stage and fly from.
Make sure items like safety pylons, gear/cases, safety personnel, crew vehicles, etc are all clear of the full shot. This can be especially challenging when dealing with high long shots that take in a large amount of landscape.
Also be aware of reflections on water, windows, etc where the UAV can come into view in the shot indirectly.
A little planning and thought can go a long way to preventing a ruined shot or additional work by someone in post production.