Next time your at your field alone and you see some one driving in just grab your TX and stand in the pilot box and fly an imaginary airplane you can do imaginary loops and rolls maybe even through in a few high speed passes. You can have a ball doing this and the look on the other guys face when you do the ol turn to talk and then turn back to try and find your now lost airplane.

I tried this , I got so good I went looking for my plane, The people at the gate thought I was NUTS, Never found it.

The best would be to have them go help you try and find it.

Or yell "DUCK!" and dive to the ground.

Me and a few friends used to do something similar at school.
About four of us would stand in a group and look up into the sky saying wow look at that and other similar stuff.
After a few minutes, you could bet a few other people nearby would be looking up (at nothing) and someone would eventually say "oh yeah, I see it!!"

standing at a bus stop looking up and sometimes pointing also works