Planes clouds and vortices

For anyone interested, there are several great youtube videos[1-4] that show the wakes (the wingtip vortices in particular) created by various aircraft. This incident brings the Reduced Vertical Separation Minima (RVSM)[5] into question. Strategic Lateral Offset Procedure (SLOP)[6] can be used used to avoid such incidents. [1] [LINK] [2] [VIDEO] [3] [LINK] [4] [LINK] [5] [LINK] [6] [LINK]

Regarding your 2nd answer, taking off quickly after another aircraft has departed is difficult because of wake turbulence. The most hazardous part of wake turbulence is the spiraling wingtip vortices which can be observed in this neat video: [VIDEO] One notable wake turbulence incident was in 2006 at Boeing Field in Seattle where a Cessna 172 and Boeing 747 were both on final approach for parallel runways. The Cessna 172 got flipped almost upside down and recovered 150 feet over the terrain: [LINK]

One concept is "heavier than air" flight is throwing air downward. Visuals help: [1] [LINK] [2] [LINK] [3] [LINK] [4] [VIDEO]

Two quick errata: In Sound / Biology, a control inversion: low pitch (slider and sound) animates blue short hairs, and high pitch animates long red. In the windtunnel > Wing, lift is reported but the airstream remains undeflected.[1] [1] randomly, fwiw, I've used cloud deck slicing to illustrate downdraft, eg [LINK] [LINK] . Or perhaps moments of "yoink" like... err, [VIDEO] .