Airshows can easily get tens of thousands of people showing up. Most people would have no problem paying a small entry fee to offset some of the costs.
I’ve attended many airshows. They could easily recoup fuel costs by charging a fee for attendance, as airshows are almost always free. Canceling the airshow is like releasing illegal aliens.. Just a “look what the Republicans did to you”, punitive action especially since lots of airshow attendees AND PARTICIPANTS are pro-military conservatives.
I've been to several air shows over the years, in fact, as recently as last September. The largest I've attended, going back about ten years, was the Dayton Air Show. Anyway, my point is they all charge an admission fee, or at least that's been my experience.
The Cleveland Air Show fee is $19/adult and $12/children. It is an excellent show and is very well attended. I have gone to quite a few air shows over the years around the country. None has been free.