It has to be apples to apples, however there is no point using figures that are not truly representative of reality.
For example, not 1 Cobham Captain has ever been paid year 1 figures, and I doubt they ever will, so to indicate the captains salary is $105k is really misleading, as it is if the other companies are not truly representative.
My suggestion is that some one, I will with my minimal computer skills if required, draw up a table and publish the basics for each company with enough detail to paint a clear picture.
I will start with Cobham as I know those details.