My daughter in the Air Force tells me that they no longer serve SOS, which is not the same as biscuits and gravy, but close. There were two kinds of SOS: The Navy version, which is chipped beef on toast. I won't say here what the Navy called it. I grew up eating it. Mom had to learn how to make it to US Navy specs. She used the dried salty beef that comes in little jars for the meat. She made a white gravy for it. One official ingredient you would never suspect is a little nutmeg.

The Army and Air Force version used ground beef. I liked them both. Sad to see such a fine tradition leaving the AF.

Edit: After a little research I found that both types of SOS were served in both the Army and the Navy. Sometimes it was actually served on biscuits. I worked as a civilian assistant mess cook for the Navy before joining the AF, and we only used the chipped beef at that base.