just tell them your expected earnings/working conditions as a professional helicopter pilot.
I don't want to give them any more reasons to take the mick!!

We were watching a R22 coming in on a full auto and they were all going "cor he's coming in a bit fast and steep" I then had to explain to them that he was performing an autorotation; they were gobsmacked, I think they thought that helis just drop out of the sky if their engines fail, they were quietly all surprised at just how controlled and auto can be. I felt quite smug at their self exposed ignorance.
A silent and pitying look of self-satisfaction that you had more originality and were of a more interesting bent than to choose fixed-wing should more than suffice as a come back.
I've tried that but they're like a dog with a bone, same old tired jokes over and over again.
One day a few nice Eurocopters came in, my future Heli instructor came to find me to see if I wanted to look around them (I think he knew how dull ground school can be). He extended the offer to the other plank fliers, and they were out there like flies around sh!t. No, they're not interested in helcopters are they?! Two faced gits