If Odessa was closer but they turned back to PRG it would most likely be for maintenance purposes. I.E PRG is CSA home base so any engine change or whatever was required would be far easier there than getting parts + engineers out to Odessa.
Remember Swissair 111 that crashed into the sea off Novo Scotia? They had smoke in the cockpit and although Halifax was far nearer, the crew wanted to divert to Boston as it was a Swissair route, they knew the airport and knew that a Swissair mechanic could deal with the issue far quicker than would have been possible at the smaller airport of Halifax. In the end they had to chose Halifax, the rest is history.
There was also the 3 Engine BA 747 from LAX but we wont go there.
Regards.
