I'll be coming in on Delta next month connecting to the IST flight. Since I only have carry-on I'm wondering if i can just check in online and go to the AF lounge without the invitation. Would be nice not to have to go to the check-in desks and back through security.

I can't answer your question unfortunately as I don't know the answer but what I'll say is online check in doesn't always work for me with TK (UK passport). Seems hit and miss, at LAX last month worked fine but IAD this month did not. So there you go, all the best.

Thanks! I don't think I've ever had a problem with online check in and just found out that I can get into the AF lounge using Priority Pass. That means I won't need the invitation. We shall see.....

As TK and Lufthansa both fly out of concourse B, wouldn't TK pax get access to the SEN and Biz lounge?

You can get access if you are XX*G or fly in C.

And BTW TK will ve its own lounge at IAD later this year:

http://www.flyertalk.com/forum/turki...tions-tpe.html

[apologies for advertising my own thread:D]