We flew back from Sabiha airport today, with Peagasus, however we had been in Istanbul for a couple of days. When we flew in from Dalaman I did see a transit lane for international flights . We checked in with the mobile app, and had boarding cards on our phones, these were acceptable at both Dalaman and Istanbul which made the whole process much quicker, we only had hand luggage so straight through to security at both airports. There were no queues at passport control at Sabiha airport but this was leaving not arriving.
Sent from my iPhone using Tapatalk