As a kid in the 1950's I was living in the U.K. as my father was stationed there for a number of years with the USAF. As a navigator, he was involved in the U2/Gary Powers stuff and flew a lot of secret missions connected with the U2s. At that time, my mother had no idea what his various missions were about. He only told us a bit about it much much later, not long before he died in 1989. And even then he didn't tell us all the details, so yes, the military is always pretty top secret in certain things.