With update 1.53 “Fire Storm” comes the move to Dagor Engine 4.0 along with significant changes to the game thanks to alterations in the visibility of ground vehicles and aircraft. We hope that you can check these changes out for yourselves and enjoy the work we’ve done in "Fire Storm" very soon.

...How is visibility for an aircraft defined? One might often hear that “they’re more visible in real life” or “you can recognize an plane’s silhouette from X kilometers away” or “in the game Y is more/less visible, more/less realistic”. It’s far easier to detect an aircraft by sound than by sight. On a windless day, in clear weather, the sound of the engine can be heard from 10-12 km away, while an aircraft can only be seen without binoculars at a distance of 8-10 km...

The War Thunder Team