USAir had planes with the VJ suffix on their registrations long before ValuJet arrived on the scene. I think that is why some ValuJet aircraft had the VV suffix. They wanted to keep the numeral part of the registrations consecutive, but in some cases, USAir had the same numeral with VJ on the end of it, so ValuJet had to use something else. I know it's kind of confusing, just like Northwest's use of the US suffix, which causes some people to think their planes are ex-USAir. But Northwest used it first.
Fly Eastern's Golden Falcon DC-7B