Though no-one knows for sure, it's also been rumored that the fighter designation was done as a security measure to hide the true purpose of the aircraft, or that the F-117 designation existed in early planning documents and was simply never changed once the aircraft became a reality.

It's also not the first attack aircraft to carry a fighter designation; the F-111 long-range attack aircraft also carried that designation (though in that case it was because the aircraft was originally meant, in part, to fill an Naval air-defense fighter role).