Let's imagine a trip on an airliner in the future. Since the cost of fuel is going up,we'll be flying in a human-powered aircraft,which means we'll be flying without using any fuel. First,we must qualify for buying a ticket. The airline we'll be flying on doesn't want anyone to collapse of exhaustion during the flight,so all passengers must pass a physical examination before they are allowed to buy a ticket. To qualify,we visit a medical clinic that specializes in screening potential passengers for human-powered airplane flights. The doctor at the clinic asks us to sit on a stationary bicycle and pedal it for one hour. While we pedal,the doctor takes readings of our heart rate and respiration. After the doctor is satisfied that we are healthy enough for a human-powered flight,we are given a certificate of health,and then we can go to the ticket agent and buy the airplane ticket. The ticket agent will not sell a ticket to anyone unless they show the certificate of health.

Now,it's time to get on the plane. The aircraft is large enough for 200 people,it has a pair of engines under each wing. The four engines are not powered by gasoline,they are powered by electricity. The electricity comes from 200 people pedaling. When you get into the airplane,you notice the interior is plain,very plain. There is no carpeting on the floor. The lack of carpeting is part of the plane's design. Carpeting was left out because carpeting adds weight. Everything in the plane is designed to weigh less than the items found in a conventional plane. There are two restrooms in a conventional plane (one for men,one for women) but in a human-powered airplane,there is only one restroom. Since one restroom weighs less than two,the men and women in the human-powered plane must take turns using the same restroom.

An airline stewardess tells us to get in our seats,and prepare for flight. The seats are wide and comfortable,and there is a set of pedals on the floor in front of each seat. All of the 200 people on board must pedal,since their muscle power is the only source of power for this aircraft. The stewardess signals the passengers to start pedaling,and everyone places their feet on their pedals and begins to pedal. Under each set of pedals is an electrical generator. When you pedal,the pedals turn the generator,so the generator produces electricity. The electricity produced by the generators goes through cables to the electric motors that spin the plane's propellers. The plane moves slowly at first,as it taxis towards the runway. After a few minutes,the pilot announces that we are ready for takeoff. Soon,the plane is climbing into the air. All the passengers must continue to pedal,or the plane will lost altitude,due to a loss of power.

If the flight lasts several hours,you will not have to pedal continuously the entire time. You will be permitted to have a five-minute rest break once every hour. During the rest break,you can use the bathroom,or just get out of your seat to stretch. The rest breaks are carefully organized so that rest breaks don't coincide. Obviously,the plane would not have enough power if everyone on board took their rest breaks at the same time,so the stewardess organizes your rest breaks so that there is no danger of significant power loss. No more than five percent of the passengers are taking a rest break at any given time,so at least ninety-five percent of the passengers are always on the job,producing power for the plane. After a few hours of flight,the plane lands,and all the passengers can leave. This human-powered flight cost only a fraction of what a flight on a conventional airliner would cost,since the human-powered aircraft does not use expensive fuel. The human-powered aircraft does not pollute the air,or contribute to global warming,either. Welcome to the future of air travel.