Here's the link I use to find out info for international jumpseating. Don't think CO Connection would be a problem. The only one who is somewhat picky is AA. The only reason PSA and Piedmont can jumpseat internationally is cause in CASS, since they are wholly owned, their airline code is US. Since AA has an international agreement in the system for jumpseaters listed with US stating they are approved, PSA and Piedmont are approved.

Jumpseat Information > Jumpseat Resources > Airline Jumpseat Policies

From experience, for DL in ATL go to Terminal E and check-in at the special services ticket counters at the top of the escalators. CO in EWR, see above. I've also Jumpseated out of HKG on UA and the agents at the ticket counter knew exactly what I was asking for (a first in stations outside the US) and were able to list me at the ticket counter 60 minutes before departure.

I will say always try and have them list you for a return in the US if you can. And remember it doesn't hurt to ask. My inbound flight was running late and I was tryin to go ATL-DXB and showed up at the ticket counter in E 45 minutes before departure. I just asked the agent nicely to try and list me and sure enough the system listed me even though DL states the cutoff is 75 minutes. She was shocked as well but I figured if there were restrictions it would have been denied through the computer.