The good thing is the military knows what it was.
I was the project engineer at the Klamath Falls airport between 2000 and 2002. That airport has both commercial/private aircraft and is also home to an Oregon Air National Guard fighter wing. Additionally I have worked on several airports, both military and commercials and it is not unusual to see non-based transient military aircraft use these facilities for re-fueling or stop overs. However, at the Kfalls airport I did see a couple of aircraft do low fly-bys and to this day have no clue what make or model they were.
My project was right on the end of the runway and these birds were less than 100 feet above me.