[original media no longer available]
Under the right atmospheric conditions, condensation can form, even at low speeds, as moist air is accelerated over airplane wings. This acceleration causes a local drop in pressure and temperature, which can cause water vapor in the air to condense. The condensation can sometimes get pulled into the wingtip vortices shed off of the wings, tail, and ailerons of an aircraft, as in the video above, making the aerodynamics of the airplane visible to the naked eye.