Flies at altitude.
There were several flies in my light aircraft this past weekend that had a chance to explore the world more than a few hundred feet from their place of birth. A handful of them piled into the cockpit before I took off. They were then uplifted to ten thousand feet and flown 350 miles across Australia before being dropped off.
I can say with confidence that they do get quite sluggish up at altitude and tend to just wander about slowly on the windscreen or quietly gaze out the window and tend to get more frisky once you descend back to lower levels. Maybe they need denser air to fly properly.
I was glad for the company actually as it was a boring flight and they helped me to pass the time. Sad really!
cheers
Vic