If I'm not mistaken, FX owns all their feeder aircraft (Caravans and ATRs) and contracts those other companies to operate them. For that reason, FX maintains much more operational control over their feeder system than UPS, who just contracts with the lowest bidder. I think Corporate Air is based in Casper, WY, or at least has a pilot base there. I don't know where Baron's HQ is, but they fly around Nebraska quite a bit. Wiggins is based in the northeast, either VT or NH.