Jetpacks: been explained. They exist already, in various forms. They're just insanely expensive and occasionally really horribly dangerous.
Space: Oh for the... I'm sorry you don't get to ride in the enterprise, but there are more pressing concerns right now. People are not douche nozzles for not wanting to fund your personal wet dream. Maybe they have dreams of having a job again after six months or a year or two years of unemployment. The earthlings of the Star Trek universe live in a Utopia, we don't. It doesn't mean give up all hope, or stop trying to learn more about the universe, but it does mean that when you complain about the rest of the country being unwilling to contribute their nonexistent surplus to something with only a very long-term, indefinite and uncertain benefit, it sounds incredibly childish. Also, suggesting real scientists lie to the public about their findings is not only insulting to the integrity of the scientific community but guaranteed to backfire when the magical moon oil suddenly disappears as quickly as it appeared. Humanity is unlikely to abandon the dream of space travel, or working toward it. We have too many nerds for that. It's just going to take longer, and given that we weren't going to be taking a wormhole jump to Alpha Centauri anytime in the next few hundred years, or quite probably EVER, I'm not really heartbroken that there's no one putting around in orbit right now. We'll get to it, geez. You really wanna make the future happen, invent the replicator and the transporter and figure out how to consistently and controllably move matter or data faster than light. We can do that, space travel will be small beans.
Vat meat: would solve some problems, definitely not all. I mean, the issue with starving people is mostly distribution, not quantity. North Americans probably throw out enough meat (and veggies, and grains etc.) every day to feed a goodly chunk of Africa (do not have exact statistics, not going to look for them.) It does fix the ethical issue. Presupposing FDA approval, I'd be happier to eat vat meat.
Miniature and giant animals: there are miniature cattle, actually. The idea is they make better milk cows because they require less feeding, though of course they provide less meat. And there's miniature ponies and pygmy goats too. And dwarf rabbits. There are lots of domesticated animals with a miniature version, most of them for food reasons and most of which were bred to that size over centuries. Since hamsters are essentially tame vermin and bears are wild animals, we've never had equally complex breeding programs for them. None of the above mini critters were created with SCIENCE!!! in the sense of test tubes and chemicals, just old fashioned animal husbandry, same with dogs.
