i noticed this as well, however i have a 1080 max-q. i will get 60fps over open ocean when in outside view, however it dips down to 30fps inside, but only sometimes. it's very strange and it's not for lack of VRAM. usually depends on a certain viewing angle. but that should now happen with this plane as even much larger ones don't have this effect. ill see if i can take some screenshots to show you what i mean.
still absolutely loving it