The 1:56 (28mm) scale is predominately a gaming scale, and how it came about is an interesting story all on its own (mostly Scale-Creep).
Also, the 1:56 (28mm) scale for WW2 gaming is predominately used for skirmish level type of game like Bolt Action, Chain of Command, Battleground WW2 and several others. Can 1:56 (28mm) scale be used for games like Flames of War or Blitzkrieg Commander? Yes, but I have yet to see this, and there are good reasons why. But certainly, that would be visually exciting.
Don't get my wrong, I think maybe 1:56 scale WW2 model aircraft can be fun and very unique to say the least! You can use these for air combat games! However, 1:200, 1:144 and 1:72 seem to have a strong hold on this type of gaming. Regardless, I would very much like to see Rubicon Models put the efforts into making a M3 Lee/Grant, Allied anti-tank guns, or even a Brumbar long before they worked on any 1:56 scale WW2 aircraft models, but that is just me.
But getting back to the 1:56 (28mm) scale and games like BA, CoC, and BWW2. How much interest will there be in 1:56 scale aircraft? Maybe a glider or two (these will be big models), but I am guessing not much interest. Even as a marker for calling in an air strike for Bolt Action, most players just use something simple. I have a friend that uses 1:72 scale models to note the direction and path of the airstrike, but not only did he already have these, but I do not think this is common among most gamers.
Side Story:
The one game I saw that had a true 1:56 scale aircraft was a scratch build - and really good one at that - of a crashed/wreckage Focke-Wulf 189, and it was being used as battlefield decoration/terrain. However, the guy who created it did tell me he originally made it for a Bolt Action scenario. In that scenario, the Fw189 was on a recon mission, and it was shot down near German lines. The German side had to try and recover the important intel from the Fw189, and the other side (British I think he said?) was not told of this, but instead was told the German mission was something else (blow up a bridge I think?). Anyway, it seems the game had a unique outcome with an unexpected ending. I like games that that.