If you'v­e been to an airport lately, you've probably noticed that air travel is becoming more and more congested. Despite frequent delays, airplanes still provide the fastest way to travel hundreds or thousands of miles. Passenger air travel revolutionized the transportation industry in the last century, letting people traverse great distances in a matter of hours instead of days or weeks. The only alternatives to airplanes — feet, cars, buses, boats and conventional trains — are just too slow for today's fast-paced society. However, there is a new form of transportation that could revolutionize transportation of the 21st century the way airplanes did in the 20th century.