This entry is basically, Part II of Where's My Flying Car.
When will there be an aircraft in every garage? In a word - never. Okay, never's a long time, so perhaps I shouldn't be making such a sweeping statement, but I really don't think that it will happen anytime soon.
People have limited incomes, and an aircraft will always be a sizeable investment. I think the automobile industry makes for a good comparison - it's fairly mature, and aircraft are very similar in complexity to an automobile. Even if aircraft were to be mass produced, they're going to be similar in price to automobiles. That's not cheap. People aren't going to go out and buy an aircraft in addition to everything they already own. So, since aircraft would presumably be fulfilling many of the purposes that people currently use their automobiles for, it would stand to reason that a majority of people will purchase aircraft only when they make good substitutes for their automobiles. Unfortunatley, there are two big reasons why I don't think that's the case.
For one thing, flying will always carry higher stakes than driving. You can drive a car that's in bad repair, or with a rough-running engine, or that has a low tire, or any myriad of problems. Yes, it may be a little more dangerous, but I've been in an automobile several times when it's broken down or gotten a flat, and all that happens is that you pull over to the side of the road, and have to get it fixed. Sure, it's an inconvenience, but it's rarely life threatening. That's not the case for an aircraft. If you're in the air and have a problem, you still need to get back down. Yes, pilots train for this, and yes, many emergency landings are performed safely every year, but many emergency landings also result in accidents. And there are some regions that just don't have much area suitable for emergency landings (lots of trees, uneven land, urban areas, etc). So, you always need to be sure that an aircraft is in good condition before climbing in to go somewhere - you need to do your pre-flight inspection every time, to make sure that nothing's happened. You can't just hop in to run down to the grocery store or to fly to the mall to do your Christmas shopping like you could in a car.
It's common to hear the claim that airplanes are safer than cars, or that the most dangerous part of a flight is the car ride to the airport. Statistically, that's true for airliners, but not for other types of flying (more info). And the only reason it's true for airliners is because there's so much maintenance on the airplanes to ensure their mechanical safety, and so much training for the pilots, to ensure that they can cope with any situation. Perhaps pilot training can be replaced with a sufficiently advanced computer control, but maintenance will always be an issue. As I wrote in the previous paragraph, any aircraft will require an inspection prior to every trip, which really does limit their utility for personal transportation.
The other major factor I see is weather. Wind, turbulence, fog, heavy rain - these are all big concerns for flying. Yes, they're concerns for automobiles, too, but you can continue driving a car in far worse conditions than what would ground an airplane. I've been caught in heavy thunderstorms, where I had to slow my car way down and it took me twice as long to get to where I was going, but I still got there. Had I been flying, I would have had to turn around to go back home (actually, before flying, I probably would have checked the weather, and never attempted a flight into conditions like that to begin with), and I never would have gotten to where I wanted to go.
To expand a bit on this weather issue - it's not just a matter of getting sensors that could peer through fog and rain, or having the skill to safely land in gusty conditions, although those are important. It's the fact that aircraft are shaken around a lot more by wind than cars are, because it's the atmosphere itself supporting the aircraft. Anybody who's been on an airliner knows what turbulence feels like - just imagine what a really bad thunderstorm could do. Small planes can get caught in updrafts or downdrafts that are so strong, that no matter what the pilot does he'll get pulled along with them. Maybe the aircraft of the future will have big enough engines that this won't be a problem, and maybe they'll be able to fly high enough that they'll fly above most storms (though being fully pressurized just adds to the maitenance related safety concerns), but that still won't help when a powerful thunderstorm's sitting right over top of you when you want to take off, or sitting right over top of your intended destination.
And I haven't even touched on traffic. Look at what it's like trying to get into a mall parking lot during Christmas season right now - just imagine if all those people were coming in aircraft instead of cars.
I hate to be a naysayer. As a pilot and aerospace engineer myself, I'd love to see personal aircraft become much more common. And perhaps one day, many of the problems I discussed above will be solved. But, being realistic, I have to admit that the demand for personal aircraft will never be the same as that for automobiles, and we're kidding ourselves if we think otherwise. So, when will there be an aircraft in every garage? Not in my lifetime.
I only have a very small update for today. Way back when I had my co-op during college, I figured out a way to fold a pretty good 
,along with some pictures.