I'm playing on the Xbox series X. After completing the quest: "Venus in Furs" all of the sky traffic is gone. No flying cars (Aerodines) no flying ships. I can still hear them overhead, but models are gone. I tried loading multiple saves and could not fix the issue. Finally I loaded a save right before sleeping with Meredith ("Venus in Furs") and all air - craft were back. So I did the quest again to make sure and they disappeared again. Will leave quest open for now. Hope this helps!!!