“Aerodynamics say that if drag and thrust are equal, as in this video, the plane should move forward, not stay in the same position… why is this? Because the left one runs slower? than the right one.”  Sounds logical, but what an impressive visualization.
via Unique Daily
Skipweasel
Not even well faked.
Also, if the forces on the plane are balanced it will retain the velocity (not speed) it had at the start. Since it was stationary at the start it would remain stationary.
Goober
It wouldn’t remain stationary, it would fall to the ground, having no lift.
seekshelter
both fans are also pointing at an angle toward the camera …instead of straight on…
seekshelter
and why would you do that outside where you would have wind interference?
Wes
@seekshelter: Although I still believe it’s faked, a wide-angle lens placed relatively close to the fans would give that illusion.
dandeman
another point to consider is that as the plane gets closer to the right fan it begins to hinge, but only around one spot.and at 1:05 it bends around that point. that point is where i think the anchoring string is attached
Shiver
Very obviously faked. Assuming for a minute that the wing on the paper airplane is actually a wing, lift will be created by air passing over the wing, which will keep the plane in the air. However, it will also create drag which will create a force pushing the plane backwards. This video would have you believe that the other fan is opposing this drag force by blowing in the opposite direction. However to create an equal force of, and have the plane stay in one place, the air speed from behind would have to equal the air speed from the front, which would create effectively zero airspeed at the wing, causing it to have no lift, and of course fall to the ground 
Johnny Cat
Informative Fail is informative. I appreciate the meta-side of Faked Videos.
DragonLost
actually, when thrust and drag are equal, you have straight and level, unaccelerated flight. it just so happens that an object in motion stays in motion.
dbsmall
Paper airplanes fly by the “kite/glider” principle, not because they have an airfoil.
An airfoil would, indeed, develop lift as air is passed over it.
A paper airplane wing, however, would either descend smoothly, or pitch up/stall (repeat) if enough air were present.
Bottom line: they shoulda used a real wing, and even then, I’m skeptical they’d get it precisely tuned enough.
viscousflow
“not because they have an airfoil.”
This is wrong, anything placed in airflow can generate a certain amount lift and become an airfoil – do some research. The simple principle behind this is that it is indeed “flying” or “moving forward” relative to the air around it. There’s no magic behind it. Pretty neat I must admit.
But remember anything in flight only has to do with the relative airspeed around the lifting body (or wing)
Shiver
You’re conveniently ignoring drag which would make it impossible to stay in once place as you suggest
Aeronaut
I don’t think this is a demonstration of lift/drag/thrust. I haven’t had a chance to get the fans out of the attic to try this yet but I think they created a vortex around the plane. The fan is blowing a toroid, so there’s actually a stable high pressure (low velocity) zone in the middle. Sometimes in department stores you’ll see a fan pointed upwards with a beach ball floating in the low velocity region. For the more powerful fans they point the fan off the vertical. I think the clever thing here is the video used two horizontal fans and figured out how to create a stable zone in the middle with enough updraft to keep the plane aloft. That would explain why the fans don’t point directly at each other. Or could be faked. I have to try it out.
Steve Among Steves
Poorly faked too. Notice the natural motion blur on the fan blades, yet no blur whatsoever on the plane as it shimmies or when it drops.
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