Here's a sight, two retired Swiss F-5s converted to US Navy Adversary aircraft. The Navy is going to use these F-5N's to train fleet pilots in adversary tactics.
I'm kinda surprised on the plane choice but I'm sure they have their reasons. The F-5 used to pull adversary duty with USAF Aggressors but now F-16s and F-15s do it. The Navy definitely won't be simulating SU-30's with these completely outmatched F-5s.