Back in the days of the Balkan Bombing Campaigns in the 1990s (I forget which one, but probably Allied Force), the E-3D was controlling the ingress and egress of USAF aircraft on the northern routes with the E-3A controlling the rest from a Southern orbit. The USAF was concerned that the raids on the ATO were leaking to Belgrade and therefore their ATO arrived for us via one of the F-16 Squadrons at Aviano rather than by signal.
One such morning, we took over the orbit with an F-117 raid in progress. Unfortunately, the F-117s were in silent mode and did not check in - they only checked out with us once they left theatre. We were somewhat disconcerted when one of their aircraft listed on the "black" ATO failed to check with us. About 60 minutes of fraught radio transmissions and following CSAR checklists etc followed and only stopped when CAOC finally admitted that the missing aircraft was a no-show but they had declined to tell us for security reasons!
Thanks Guys!