I tried to pull a fast one on my last AS flight by using a NW cert...doesn't work...have to have NW number in there AND it has to be Plat number. They are getting smart. However, they will offer you FC for $50 if available when you check in.
On DL, you are SOL on DL.
And if they merger happens say bye-bye to NW upgrades for CO Elites.
- HF