I was responsible, in a sense, for airshows in 4 successive years in the 1980's...
We gave a concession to a professional organiser who paid us a percentage of the gross income, ie the risk was all his. We provided an operational airfield with lots of car parking areas, good access, and lots of cooperation.
He earned income from
Concessions....food, clothing, local radio stand, aviation tat, etc, stand rental fees.
Gate takings/parking fees (one payment)
er, that's it, I think.
He paid for:
Our percentage
Displays (Often including transport, accommodation, and so on for pilots and support teams)
Police and Local Authority charges, St John attendance, etc.
PL Insurance, (very heavy.)
and probably lots more, eg fuel for displays?
In a good year he would clean up. In a bad year he took a big hit. Weather was the key, of course, affecting the displays and the gate.