Lusche,
how about looking at a "dedication" score for each model. In a given tour (or several combined) divide the total kills of a given model by the total number of kills of all players that had at least one kill with the model. This would give 1 if all player do all their killing with this model - I.e. they tend to be dedicated, and a value closer to 0 if this is a "hop on for an ocassional ride" model.
Models such as the P38G, 109F, P47D11, Ta152 are probably flown by dedicated players, while the common JABOs and carrier fighter-bombers are everyone's *potatoes*. Which model has the most dedicated players community?
P.S.,
You can do the same with K+D instead of just K to be more inline with your usage parameter.