The eccentric journalist, who was the subject of Gilliam's 1998 film "Fear & Loathing in Las Vegas," was cremated and his ashes were shot into the sky amidst fireworks near his Colorado home on Aug. 20 -- six months after the 67-year-old writer committed suicide.
Johnny Depp, the actor who played Thompson in Gilliam's movie, reportedly financed most of the event.
"I think it's a brilliant way for Hunter to go," said Gilliam, the former "Monty Python" troupe member and director of the new big-screen fantasy, "The Brothers Grimm."
"I just think, the next morning, everyone in Aspen must have been washing their cars trying to get Hunter off," he chuckled during a phone interview with UPI Wednesday.
Asked if he thought Thompson would have gotten a kick out of the blast-off, Gilliam replied, "He would have laughed all the way to the grave."
The filmmaker said he was unable to attend the event, but watched news accounts of it on television.