"Steven P. McNicoll" wrote in message
.net...

I don't think you understand. Class C services are provided to all
aircraft within the Class C airspace itself, and to all participating
aircraft in the outer area associated with it. The outer area is not
marked on the chart, it is normally the area within a twenty mile radius
of the Class C primary airport and extends from the lower limits of
radar/radio coverage up to the ceiling of the approach control's delegated
airspace excluding the Class C charted area.

OK, so how does this work? Two years ago, enroute OSH for the fly-in, I
approach Madison with flight following. I'm given vectors, despite the fact
I'm at 11,500 feet.

Just how far up does their airspace extend?

I'm glad this came up. I've wondered about that (off and on) ever since it
happened.