In FSX invisible txiwys for ai

I used to be able to do this in FS9, making a txiwy narrower than 2 feet, create a txiwy all around the bay and back. I ended up with a nice sail boat taking off and sailing around the bay and back at specific times.

In FSX I'm trying to make the same for a friend of mine to make an ai boat to follow it. But of course all I am getting is a water taxiwy on top of built up ground to the elevation of my airport even though I specified 0 elevation. I tried ADE to flatten this, but the compile didn't work. Haven't tried Xbuilder yet, but I'm fairly sure I'd get the same results.

I think I could make another airport, so to speak,.... at water level. Bob

And yes, you would have to make your 'airport' at sea level.
Of course in FSX you can also make use of the 'living world' AI and make your route with AIBTC for instance. You would not need another airport then.
Hi Bob,

AIBTC is a seperate program for making your own living world sea (vessels)and land (aninals and vehicles) traffic. A more or less similar but more complicated tool is found in the SDK. Maybe FSX KML can do it also, I am not sure though.