Did John Lennon and Richard Nixon have anything to do with it?! Aha!
For what it's worth, the FAA guy who certified my husband for his pilot's license said that the Kennedy Jr. was tanked up on coke and pain meds for a recent surgery, and that a flight instructor on the ground told him NOT to go up because of that and his miniscule number of flight hours, and Kennedy did anyway.
Y'know, stuff that didn't quite make the news.