As the ultimate form of transportation, flying needs no introduction.  For nearly 100 years, a very fortunate minority of mankind has been able to utilize aircraft for personal travel.  It seems intuitive that the next step in lifestyle advancement would be for some sort of aircraft to replace the automobile, just as the latter replaced the horse at the turn of the 20th century. 
 
The members of the “baby boom” and subsequent generations were all promised “flying cars” by the futurists for obvious reasons.  Yet for reasons that are almost as obvious, there have been no viable personal aviation products successfully introduced to the marketplace.  All previous attempts at the “flying car” have failed, because none of them overcame all three primary barriers to the formation of a multi-billion dollar personal aviation market:

• Cost
• Ease of Use
• Perceived Safety Concerns

While there are private aircraft in use today, they have very little market penetration due to their very high acquisition and operating costs.  In order to unseat the automobile as the dominate choice in personal transportation, the real breakthrough personal aviation technology will require a retail price and an operating cost structure approximately the same as the average family automobile. Certainly, in order to fit the popular “disruptive technology” model, breakthrough personal aviation craft will have to cost less than a car to acquire and maintain.
 
One of the primary advantages of the automobile has always been convenience.  For most people, their automobile is just a few steps away.  When contrasted with virtually all aircraft, this is very convenient indeed; most airports are farther away from people’s front door than their typical destination!  Therefore, the breakthrough personal aviation technology must be of the Vertical Take Off and Landing (VTOL) variety that does not require forward speed, much less a special runway, to become airborne.  You must be able to take-off in your driveway.
 
Until now, the great paradox of aviation has been that the most versatile aircraft are the hardest to operate.  The most common VTOL aircraft – the helicopter - is notorious for requiring special training, as well as acute manual dexterity and coordination.  The breakthrough personal aviation technology will have to circumvent this paradox; the craft must take off and land vertically, yet be as easy to operate as an automobile.  In short, it must approximate the average automobile in convenience.  A person must be able to walk 20 feet out the front door of his house and fly straight up - without mastering specialized skills.
 
The unique advantage of any aircraft is also its largest perceived liability.  Anything that goes up must also come down.  With an automobile, most people expect that even a catastrophic failure of one or more parts will yield a worst-case result of being stranded by the side of the road.  Whether an exaggerated perception or not, people expect that virtually any failure of any part of an aircraft will have life-threatening safety consequences.  To address this concern, the breakthrough personal aviation technology must have “highly available” or intrinsically fault-tolerant lift and propulsion systems.  Indeed, any potential customer of a breakthrough aircraft must be assured that the vehicle will remain safely airborne even if one or more basic components fail.  In short, the breakthrough personal aviation technology must be capable of much higher reliability than the average automobile.
 
For mass-market personal aviation to finally become a reality, all of these problems must be solved simultaneously with one technology.