Originally Posted by
craigthemif
I doubt that a IST-FRA-USA flight was on Turkish Airlines, in which case this thread belongs in the forum of the operating airline. (LH?)
While we speculate OP’s situation... doesn’t TK interline with *A partners like LH/UA etc. - the potential *A candidates for the FRA-USA leg. I would assume they do and not just on code shares.
So maybe OP was flying AA or DL or something like that out of FRA.