TK will be starting IAH-IST service on 01April 2013 with their 777-300ERs. They will have a late afternoon departure compared to when all the European departures on foreign carriers leave except for the 2nd BA flight to Heathrow. A bit of history, LH served FRA-DFW in the late 80s first and then added FRA-DFW-IAH extension. I believe in the 90s they gave each city their own nonstop, and now IAH gets the A380 while DFW gets an A330.