Looking at booking ECN-IST-JFK and return. Will not be leaving the IST airport. travelling on a US passport. Will I have to get a visa upon arrival in IST (or online beforehand)? Am I correct in understanding that ECN-IST is considered a domestic flight?

And to complicate matters (or maybe not), I live in the RoC (have a residency permit) so I will have no stamps in my passport from the TRNC. TRNC does not stamp passports when crossing by land from the RoC to the TRNC.

I will be driving to the RoC the same day I arrive in EVN. Will TRNC to RoC customs conditions apply when I cross from the TRNC to the RoC? Or will RoC customs conditions apply as if I were just arriving into the RoC? The TRNC-RoC customs conditions are more limiting than if you arrived in LCA.