You might also mention the "Missing Man" formation of planes which fly over a funeral. A very moving symbolic display.

Also, I wish to note that when a Marine, sailor, or soldier is laid to rest with military honors, the detail will fire three rounds (in unison) in salute. That is not a 21-gun salute as some think.

The 21-gun salute is reserved for a head of state, living or dead. I've been part of a burial detail, and we tended to have 6 riflemen firing the three rounds after serving as pall bearers and folding the flag. After the firing, the officer in charge would present it to the widow (mother, father, etc.) with the words, "On behalf of a greatful nation."