Originally Posted by
bgriff
1. Correct, you should be able to go direct from economy to business. Note that for the Delta flight, you should also check that "Delta One Available with GUC" appears under the flight when you are searching to buy a ticket on that route and date while signed in on Delta.com. (That availability does now appear to align with Z class, but it's worth double-checking.)
Hmm. The website is silent on this point. For all other (connecting) flights on the same day it says either available/unavailable or unknown, but for the JFK->CPH in particular there's nothing.