Taylor Aerocar III. (from Wikipedia, photo released into the public domain by the author).
Basically, Baby Boomers and the government made flying cars (as well as nuclear power and nanotechology) impossible. Hippies undermined the pre-existing cooperative culture that had enabled large business organizations to function and innovate, but government funding of science was directly counterproductive. A note from the review on the latter (quotations from the book):
“A survey and analysis performed by the OECD in 2005 found, to their surprise, that while private R&D had a positive 0.26 correlation with economic growth, government funded R&D had a negative 0.37 correlation!” “Centralized funding of an intellectual elite makes it easier for cadres, cliques, and the politically skilled to gain control of a field, and they by their nature are resistant to new, outside, non-Ptolemaic ideas.” This is what happened to nanotech; there was a huge amount of buzz, culminating in $500 million dollars of funding under Clinton in 1990. This huge prize kicked off an academic civil war, and the fledgling field of nanotech lost hard to the more established field of material science. Material science rebranded as “nanotech”, trashed the reputation of actual nanotech (to make sure they won the competition for the grant money), and took all the funding for themselves. Nanotech never recovered.