P47 the reason why airport fees were taken out of the fare and shown separately are more complex than simply not wanting to pay commission. Actually, I believe that the non-payment of commission was a result rather than a reason.
I think the real driver was the ending of duty free inside the EU. The airlines believed (BA in particular) that the airports were making a lot of their income from duty free sales. The airlines were scared that the loss of that revenue would cause the airports to increase their fees which would force the airlines to raise their fares to cover the additional airport charges. So, in a bid to keep their fares low(er) the airlines extracted the airport fees to show them separately.
Caused some problems in the industry forums because the desire to show the fees in what had always been the "Tax" box on the ticket caused a lot of discussion and led to the remaining of that box taxes/fees/charges.