Gotcha! Not WW1 aircraft, nor even planes - it's a Type VII U-boat in calm conditions in the North Sea, in Silent Hunter 3 (Grey Wolves Expansion OneAlex Edition - latest version 1.47 includes updated clouds - get it here: https://www.youtube.com/watch?v=hhL1C-WDRWA )
That looks great. The clouds and lightning in the video was cool. It'd be awesome if they could somehow make the water transparent like SH4 but that may be beyond the limits of the engine. Either way, SH3 never looked so good.