There are 4 outcomes to this riddle:
First is the typiocal most common outcome. The person initially thinks the treadmill actually slows the plane down (based on the wording of the question), and says no. After the question gets explained further, the person realized their folly and changes their answer to "yes".
The second outcome is when a person is presented with the riddle, but instead of going with gut instinct, they think about it a little more. They come to the initial conclusion that the plane will take off, because they are able to catch the fallacy in the question. They also realize that this is a tricky question and other intelligent people may easily fall for it.
The third and fourth outcomes are the most common. The third outcome is when the person thinks they're hot #### and has it all figured out. They say it won't take off because the "plane has no airspeed". When explained the premise of question a little more clearly, they (out of arrogance and/or stubbornness) refuse to think any differently and will argue on and on and on.
Of course the fourth kind (which seems to populate this place) are the kind that believe it will takeoff, but who also believe that if you think it won't, you are the biggest moron on the face of the planet. The third and fourth personalities collide and produce 9 page threads throughout the internet's forums.
Anyways, on a side note, I used to be based out of the airport where they filmed this myth. It was nice seeing my old home on TV. I had no idea they filmed it there, and am quite curious to know when they did it. When I was based there, I flew pretty much every day, so I', kind of surprised I never saw them doing this. If I knew the date I could check my logbook and see what I was doing on that day. Most likley I was in my night flight stage, where I was waking up at 8PM, flying all night, then going to bed at like 11AM

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