Wow, there are so many reasons this is a terrible idea.<p>1. It doesn't actually solve the problem it sets out to solve (crosswind landings). To the contrary, a circular runway <i>guarantees</i> that if you have any wind at all then you <i>will</i> have a crosswind at some point in the landing. Not only that, but the apparent wind direction will be constantly shifting during the landing, making the landing even more difficult than a normal crosswind landing.<p>2. Flying in a circle at a low airspeed and at low altitude is absolutely the single most dangerous thing you can do in an airplane. When you are flying in a circle, the outboard wing is moving faster than the inboard wing, and so if you are flying close to stall speed the inboard wing will stall first, resulting in a spin. It is possible to recover from a spin but you have to descend in order to do it. If the spin starts at low altitude there is nowhere to descend to, so you will crash. Spins on approach to landing are one of the leading causes of fatal crashes in small general aviation aircraft.<p>3. Airport approach and departure procedures are designed around the fact that runways are aligned in particular directions.