Sending 4 jets to an air show can be easily justified. What is criminal is sending 100 maintainers to look after 4 aircraft ! An outrageous waste of money. I'd love to see the business case for that one.
Totally depends on what they are doing whilst there, if they are say flying day and nights you will need two shifts, so that is 50 for 4 aircraft per shift, so if you have say have per one aircraft an SAC tech or 2, Corporal, Sgt, Chief per trade, x that by Avionics and Airframe/ engines, armourers etc, add a Flight Sgt in charge of a Shift, two or three Safety equipers, Storemen, refueller, possibly catering staff, and WO/ Jengo/ Sengo between shifts, then possibly the odd bay chappy, rag packers, lox if they need it, it soon mounts up.