content: Lets talk about instrument procedures. Yes, theoretically you can land/take-off from any given point in the circle. But when it's foggy... then what? Are they going to have 36 different RNAV approach procedures for every 10° of the circle? RNAV typically have 8 different fixes each. Imagine the controller's screen... it'll look like a circular loom. What about ILS... how is the ILS going to work? Are they going to have 36 different ILS systems set up with 36 different assigned frequencies? They take a lot of effort and money for constant testing and certification too. 2 ILS systems per runway now becomes 36...not very cost efficient. If there are several airports in close proximity, they'll run out of radio frequency (either that or there'll be bleed between the frequencies if the weather is less than perfect). How do you add an extra runway when it gets really busy? An outer ring? How do you do plan approaches that don't interfere with the inner ring? It seems like too much dreaming, and not real questions being answered.