Are you using the file cvn_71tutorial.zip? If so...you have the same problem I had for a while. I finally fixed it, though, by adding a flatten line and then carefully adjusting the elevation of the airport until it was the height of the deck. Can't do it now, but I'll post a shot when I can.
I'm not happy with the results, though - it looks quite bad :-/. Added some AI but haven't checked to see how they function

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- Kevin
