Thanks Joe

I should have been more specific with my question. I was referring to the first combat casualty in the AEF's Air Service. I suspected it was Miller on 9 March, and am sure that he was the first AEF pursuit casualty.
I was wondering if there were any KIA or WIA in observation aviation, which had starting flying a couple of months earlier. I don't know of any, but I'm not an expert in AEF observation aviation.
I think Miller's death is pretty significant because, Miller's courage not withstanding, it tells us something about the decision-making process that placed him in command of the 95th Aero Squadron. He was not qualified for the job.
Raoul Lufbery could have been in charge of the squadron, same as Lafayette flyer Jean Huffer, who took over the 94th about that time.