Sounds like you need a union

Seriously though, some instructors I have known are salaried. It works both ways though. I know those ATP instructors only get paid $1200/mo regardless how much they fly. Others (Daniel Webster College I think) pays a salary plus flight pay when you are with a student. If you're bored out at the airport, stuff envelopes or something when you're not with a student. When I was instructing in college it was a good time to do homework and or study.