Ah yes, I've seen my fair share of "Thunderbird" and "Blue Angel" shows. They are something very cool to see.
I've been wanting to start a topic on millitary challenge coins but just never have. My father, who has been in the service for nearing 22 years (but only really started getting into these coins around ten years ago) has lots of these. He even has them in a wicked cool display case my mother got for him for christmas one year. They are by far the raddest medals I've ever seen. I like them a lot.
It is kind of a custom in the military community to exchange these coins. Usually each squdran has its own coin with a number of squardrans in a unit, and then the unit has its own coin. And then sometimes the squadran and unit commanders have their own personal coins made which they distribute usually to people who deserve some sort of merit. My father has been a squadran commander three times, so he has obtained and been personally given several of these coins. I should probably post pictures.