I've done a lot of video with gyro stabilized mounts. I flew the photo plane for the Wings To Adventure TV series. We got super air-to-air shots out of an A36 Bonanza with the gyro. I currently have the smaller unit.

http://aerialexposures.com

Whether it's needed for stills depends on many factors. Focal length, intended use, resolution of the sensor, and much more.

Bottom line: probably not unless you have special needs.

My evo gp pro is suppose to show up tomorrow, I'm looking forward to trying it out with my virb ultra 30. I know I won't be able to stick the gimbal out the window but I should be able to get some good video from inside the cockpit.

I've found that the in-body image stabilazation in the Sony A7ii is impressive for stills and video.

And, it sounds crazy, but the iPhone 7plus video stabilization rocks.

I have one set up t shoot through a camera hole on the bottom of an aircraft. Shot with a digital camera, did take some photos with it, but never did take the time to really make it work! PM me if interested, I'll send you some pix.
GT