[ertemplin]

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: https://www.youtube.com/watch?v=dfY5ZQDzC5s

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: https://app.ntsb.gov/pdfgenerator/ReportGeneratorFile.ashx?E...