I didn't have internet on my iPhone today and tried the StackExchange app (I rely on you guys being online - as most people do with google).
All the other apps (FB, LI, etc) have a "No Internet Connection" message, the StackExchange app just comes up with the blue gradient/shaded background.
Dont think many people have encountered this, so I am letting SE know as a suggestion to have a message (so people know its their connection thats down not the SE app hanging on start up).
edit
It wasn't the first time I opened the app.
You're right the app opens in airplane mode (I am typing this offline).
I was ready for someone to comment "screenshot or it didn't happen" and this is what it looked like.
The weird thing was that I had reception, just no internet, maybe vodaphone was down and that's why no one else has seen this. Also terminating the app and restarting didn't fix it, I still got the empty blue background.
I do believe ShadowWizard that there would be a message like the one below when posting in airplane mode:
Happy to post logs (let me know where to find them). If there's any other diagnostic info I can provide let me know, maybe a dump or something, I don't know how to debug iOS/objectiveC apps but if I can repro it again then...