Sounds like this may have been an one off delay, as you had a 3 hour buffer and still missed the flight.
Originally Posted by
invisible
Some includes TK. We were flying Business with TK, and asked about bags interlining at IST, but the reply was 'I don't see your UA flight in system' and that was the only reply I got.
Did you present a printout of your UA flight to the TK check-in agent, especially when it's on a separate ticket. A reminder to the agent that this is on a separate ticket would have explain why the flight is not on the reservation. Then again, not all *A airlines would interline your bag off of separate reservations, and it would not made a difference in this situation.