I probably screwed up our return flight, but I'll give you as much info as I can (without any rationale behind why we ended up here):

Flying CAI-IST-ORD with 2 hours and 20 minutes between when the CAI to IST flight lands and the IST to ORD flight takes off.

Each leg is on a seperate ticket/reservation. We have no checked luggage - only carry-ons. The CAI-IST flight is on Egyptair booked into Business Class I (discounted award travel) through the Canada Aeroplan. The IST-ORD flight is on Turkish Airlines booked into Business Class I (discounted award travel) through Miles & Smiles. We are US citizens with US passports. So, it looks like according to most everything we have now read and the conversations we've been able to have with both Egyptair and Turkish Airlines, upon landing at IST, we will have to deplane, clear customs and immigration, go to the Turkish Airlines counter, get a boarding pass, re-enter through security, and then make it to our gate. We will already have a multi-entrance visa for Turkey. I was originally assuming / hoping we would not have to go all the way out of the secured area. Apparently, if it was all booked on a single ticket, everything would be fine (my bad). So, is our understanding of what we'd need to do to make our flight out of IST correct? Is there any benefit to having (limited class I) Business Class tickets on both the inbound and outbound legs in terms of time / efficiency through IST? I assume there's no way we make the connection if we need to go all the way out to the Turkish Airlines ticket counter. The consequences of missing that outbound flight are obviously pretty bad. We're considering moving our inbound flight to the day before at some expense and a bunch of hassle ...