Boeing is offering $2 million in prizes—including a $1 million top prize—to inventors of "safe, quiet, ultra-compact, near-VTOL personal flying devices capable of flying 20 miles while carrying a single person." VTOL stands for vertical take-off and landing, meaning that Boeing is looking for something more original than a conventional ultralight airplane. Boeing is correct that there's potential for technological breakthroughs here, but in the world of aviation, $1 million doesn't get you very far.

The idea of personal flying machines is hardly new. Personal jetpacks have existed since at least the 1960s. But they have always had severe range and safety limitations, preventing them from becoming widely used.

In recent years, however, there's been some sign that this might be changing. Some people have continued refining jet-pack technology. One inventor has been dubbed the British Iron Man for his rocket suit, while an experimental jet-powered hoverboard called the FlyBoard Air was unveiled last year (it costs $250,000 and isn't yet available to the general public).

But the real opportunity for personal transportation technologies might be in the realm of personal drones. The same technological trends that are on the cusp of revolutionizing the car industry—more powerful electric motors, batteries, and software—are also starting to affect the aviation industry.

A key innovation here is the use of multiple propellers—four, eight, or even more—rather than just one or two as you see on a conventional helicopter. This design has been made possible by more powerful batteries and lighter electric motors, but it has also been enabled by better software. A quadcopter would be difficult for a human being to pilot if she had to manually control the power supplied to each motor the way a pilot does on a conventional aircraft. Instead, quadcopters and other modern electric aircraft have software that handles these low-level details automatically.

That makes these vehicles safer and more stable since redundant batteries and propellers allow them to land gracefully even if some components malfunction. New technologies also create the possibility of a new generation of vehicles that people can safely fly with much less training than is required for a conventional helicopter or small airplane.

This year, a startup funded by Google's Larry Page called Kitty Hawk unveiled a kind of flying jet ski that can carry a single passenger aloft over bodies of water. A number of other startups—including Lilium, Joby Aviation, and EHang—are working on all-electric, short-range vehicles that can take off and land vertically. Uber has ambitious plans to build a network of small electric flying machines for intracity transportation.

While the idea of electric aviation doesn't seem crazy, there are serious reasons to doubt that participants in the Boeing competition will be the ones to crack this technological nut. A big one is the size of the prize. One million dollars is a tiny amount of money in the aviation world. Larry Page has reportedly spent $100 million on Kitty Hawk, and several VTOL aircraft startups have raised tens of millions of dollars in venture capital. If you have an idea for a viable personal flying machine, that idea is worth a lot more than $1 million, and you might be better off going straight to venture capitalists.

On the other hand, not everyone has ready access to venture capital money, so the Boeing competition might provide an opportunity to an individual or small team to bring innovative design ideas to a larger audience. Under the contest rules, inventors retain rights to their inventions, leaving them free to commercialize them after the contest is over.