Originally Posted by
Orwaid
Most international upgrade rewards are only good for one sector. So for example on TK, I think they would only upgrade you from JFK or ORD-IST.
Well, on TK those are the only segments you'd be flying to IST anyway on TK metal. But the point is well-taken with respect to, say, BA or LH.
And you would probably have to buy an Economy Comfort ticket.
Another valid point (should be added to my above post, and related to questions #1 & #3) -- What class of service are you allowed to upgrade to/from? I think BA only allows 1-class upgrade, so coach-to-premium economy or PE-to-business. No coach-to-business. I think VS, on the other hand, does allow coach-to-business upgrades for more miles (bypassing premium economy). AFAIK, only an issue with BA/TK/VS/AF.