To add to what Larry's said Jet engines also cause significant turbulence behind the aircraft in question.
I personally will not takeoff behind any aircraft larger than a light twin, including an MD80 or DC8, Gulfstream 5 etc... even though ATC does not consider these aircraft to produce significant wake turbulence, for at least 2 minutes to allow the wake to dissipate. I disagree with Larry in taking off below the wake due to the fact that the wake is descending the entire time after takeoff, or while on approach to land. If necessary, wait 1 minute and then lift off sooner than the departing aircraft and turn out sooner, and while climbing out, "slide" the flight path up wind of the runway and parallel the departing flight path. More good reading is in the FAR/AIM, in the AIM section on wake turbulence. Just change the stated aircraft from large to smaller jets. Colin KSFB
