Are there exceptions where domestic first RUCs are not controlled by Z inventory? I tried using an RUC on a redeye flight out of Seattle. Z fares are listed. However, no certificate availability is showing up - oddly not even GUC space. I booked via my corporate booking tool so I called Delta afterwards to add the RUC. They said I could waitlist with the RUC. But if a Z fare is available, shouldn't there be upgrade space? This is a flight with regular first only (A321neo) - no Delta One.



Dave