Steven P. McNicoll wrote:

Ehh? Very close to ORD the controlled airspace goes down to the surface.
None of that surface is Lake Michigan, however.

Then it would be pretty hard for a seaplane to be taking off there, wouldn't it.

Along most of the Illinois Lake Michigan shoreline controlled airspace
begins at 700' AGL.

I've got the sectional right in front of me. The class B floor is 3,000' or
higher over the lake. Now, you can be an asshole and try to pick nits if you
like, but THERE'S NO REQUIREMENT FOR THAT SEAPLANE TO TALK TO THE ORD
CONTROLLERS PRIOR TO THAT TAKEOFF, NOR WOULD THE ORD CONTROLLERS WANT TO HEAR
FROM HIM.

George Patterson
Coffee is only a way of stealing time that should by rights belong to
your slightly older self.