The dream: Sending people through tubes at speeds approaching the speed of sound.
The reality: Elon Musk practically broke the internet last year when he unveiled his "hyperloop" concept -- an elevated tube carrying people from San Francisco to Los Angeles in under 30 minutes for a fraction of the cost of high speed rail.
Musk's idea is one of many involving people traveling in tubes -- some vacuum sealed, some crossing the ocean, some reaching 4,000 miles per hour.
They sound like pure science fiction. But futurists are surprisingly upbeat on the idea.
"We're actually transporting more stuff through tubes today than by any other mode," said DaVinci's Frey, referring to pipelines. "Why not people?"
He said the technology is there, and they tend to take fewer resources to build than either roads or rail.
"I would forecast that somebody will step up and [financially] match Musk," said Global Futures' Canton. "I think he'll build it."
