GUC
 

I’m searching for a flight to Europe from basically any of the US hubs - I’m trying to use a GUC but good grief, every single flight I look there is no availability? I checked one flight and there were 22 open Delta one seats? What am I doing wrong?

One thing you might be doing wrong is not posting in the DL forum.

https://www.flyertalk.com/forum/delt...2-changes.html

DL will generally only open the upgrade inventory if they're sufficiently confident they're unlikely to sell out the cabin.