If any member of the First Family was aboard ( excluding Obama ), the callsign would be Executive 1 Foxtrot. If it was anybody else it would be SAM 2800 or SAM 2900 depending on the plane. Venus 1 sounds like it may have been a callsign of one of the fighters.
Thanks for that information! As I said, that tidbit was part of a long and very meandering thread, so possibly I got it wrong or the poster was referring to something else.