That is actually ingame from microsoft's FSX. However, i suspect there's some 3rd party payware terrain add-on involved in the pic with the Gladiator.
Don't get me wrong, i like some things in FSX a lot and even though i don't own a copy, i fly it whenever i get the chance when visiting a friend. However, the way FSX and its add-ons do certain things are inherently unsuited to a combat sim. The stock FSX terrain is not much to write home about for example and the most celebrated feature in screenshots, which is again part of a payware add-on, the clouds, are 2d overlays from real photographed clouds and not actual 3d virtual clouds.
It's great for flying around near your home town, doing transatlantic hops in an airliner with time compression and the mid-flight save capability, or zipping along at low level in some kind of STOL aircraft over a detailed aftemarket terrain add-on from a place you'll probably never visit in your lifetime like the airstrip on the foothills of Mt. Everest, pretending you are shuttling climbers there in your twin otter, there are even 3rd party developers that have managed to overcome some of its stock FM flaws (apparently, it takes special coding to get aircraft to spin properly in FSX) by clever usage of their own modules, but there are still certain limitations that would show big time in a combat sim.
I like it a lot and if i had money to burn i'd probably buy it and a bunch of add-ons (which is the high quality stuff really), but like someone else already said it's like comparing apples and oranges.
For starters, there are no satellite photos of 1940s Europe to texture the landscape with, even if there were they would take up an enormous amount of disk space, plus in a combat sim you will invariably spend a lot of time down low attacking ground targets and having the ground go all blurry on you because you're close enough to distinguish it's just a flat texture would destroy immersion completely. Also, no matter how cool the aftermarket 2d REX clouds look in comparison to the stock FSX 3d ones and the 3d ones we are getting in CoD, there's no way around the fact that for AI line of sight calculations and maintaining fair play in multiplayer we need clouds modelled in 3d. Otherwise, one could be thinking he's inside the cloud and safe, while another guy can see him just fine and is already diving on him. Just a few examples.