Given what is happening in Turkey at the moment, is it advisable using Turkish Airlines with a 2-hour transit in Turkey to my final destination; Copenhagen?
The current warning from the U.S. State Department states:
The U.S. Department of State warns U.S. citizens of increased threats from terrorist groups throughout Turkey and to avoid travel to southeastern Turkey. In light of the July 15 coup attempt and the resulting potential for interruptions to travel and daily life, we suggest U.S. citizens reconsider travel to Turkey at this time.
That would imply that, if you can avoid an Istanbul transit, you should do so.