I don’t quite know how to react to this video:
1. Desire: I want one, where can I buy the technology and bring out a range of personal flying machines??
2. Anger: WTF??? What could 40 years more development have done for this amazing concept??
3. Intrigue: If this tech existed in 1974, what the hell are they developing behind closed doors?
Check the incredibly brief wikipedia entry here: http://en.wikipedia.org/wiki/Williams_X-Jet
In fact, go back even further to the fifties: