A passenger can almost always get a seat at the last minute if he is at the airport. It is necessary to make reservations a little further in advance for tourist flights than for first-class flights, since there are fewer of them. Passengers are allowed 40 pounds of personal baggage free, and 60 pounds if they are going out cf the United States. Any excess baggage must be paid for at the rate of y2 of 1 per cent of the fare per pound, thus making it very expensive to carry excess baggage. The scheduled airliners now make 97 percent of their scheduled flights. That is, bad weather or mechanical trouble causes only 3 percent of them to be cancelled. If a flight is unable to continue after departing, the airline will always pay for transportation to your destination, either on another airplane or on a train if the weather does not permit flying.

Freight is also carried by air, along with express packages and airmail. Besides the airlines that haul nothing but freight, the passenger airlines carry some freight in their passenger planes, and many of them also operate separate freight planes. The largest use of air freight is in hauling goods that are perishable and would be harmed by a long railroad or truck haul. Some businesses have candy, fresh flowers, seafood, and some kinds of fruit regularly delivered by air. Air freight is widely used in emergencies to transport various articles needed quickly. The transportation of larger articles has been increasing, too. In 1952, an elephant was flown from North Africa to a zoo in the United States. One further service that is available in air transportation is the charter plane. Just as one would charter a bus, a plane may be chartered. Both private companies and the scheduled and non-scheduled airlines provide this service. By 1953, it had become safer to fly the scheduled airlines than to drive your own car; and the safety record of the railroads is only slightly superior to that of the airlines.

Airplane turbulence is mainly caused by abnormal air movement. The phenomenon known as windshear is the result of air masses with different pressure crashing into each other, creating air waves. As cold air in the atmosphere descends rapidly, warm air spreads and rises until little below the cold air, which then tumbles. As the cold air hits the ground it splashes and spreads out producing surface winds. All these air movements can cause an aircraft to bounce when caught in between. Experienced pilots know how to control an airplane under these circumstances, although landing and take-off require more attention.

Jetstreams are another reason causing air turbulence. The diversity in wind speed and direction at certain parts of the atmosphere can make an aircraft fly in instability. This phenomenon occurs in heights greater than 12 km over the surface of the earth, where high pressure air masses collide with lower pressure air masses ones. At the meeting point, there is a pressure change and the wind that forms results in a stream because as the earth spins it causes the wind to be concentrated in a steam between the two air masses (known as the Coriolis force).

Probably the worst type of airplane turbulence is the one caused by thunderstorms. When flying inside thunderstorms, strong upward or downward currents of air disrupt the normal airplane movement creating high turmoil. Even below thunderstorms, there are strong colliding winds, which combined with heavy rain and lightning can cause intense turbulence that may cause the plane to crash. Turbulence can also be experienced around the edge of a thunderstorm. For that reason, pilots are informed in advance for any upcoming thunderstorm in order to protect passengers from any similar situation.

All in all, air travel is a magnificent experience and airplane turbulence should not be a reason to sustain from it. What you should remember is that airplane turbulence may be rather distressing and upsetting, but it is not hazardous. Nowadays, technology has provided airlines with the ability to predict such phenomena, making air travel a safe and exciting experience.