To understand what causes airplane turbulence, it must first be defined. When two different air masses, which have separate pressures, are disrupted for whatever reason, air turbulence will result. Combine an aircraft traveling through this atmospheric inconsistency, and you've got severe turbulence.
Before the jet age, pilots didn't worry so much about air turbulence as they didn't fly where jets fly today in the 30,000 ft. range. They also didn't fly over 500 miles per hour like today's aircraft. Why is that important? Because with increased air speed, the turbulence that exists is magnified by the speed of the plane. More than 20 percent of airplane accidents are caused by turbulence. So it's very important to spot possible areas of turbulence and the best bet is to avoid air turbulence completely. That is why pilots will fly around possible storms, or even irregular land masses that can also cause air turbulence. Better to be late and land safely rather than fight the sometimes lethal forces in the air.
Planes themselves can cause turbulence! When jets slice through the air, their wings disrupt the air mass and can cause a vortex that can trail behind the planes for miles. If another plane happens to be flying in the wake of said plane, turbulence can result from the swirling mass. That is one of the reasons for planes flying at different altitudes, which can be assigned by ground control as well as the pilot's discretion.
Anticipation of air turbulence is the best way to deal with the problem. Avoidance of air turbulence means planning the air routes with the least amount of danger to the plane and it's occupants. Computer-aided flight routes and meteorology experts can predict where the most significant amounts of the turbulence might take place, thereby created an efficient and safe flight route. Even areas of tall buildings and mountains can be the cause of the turbulence, so it's important for the communication of ground control and the pilots to be in touch before and during the flight.
A lot of the problems associated with air turbulence can be avoided with better detection systems. A system to incorporate every known factor from weather patterns to other aircraft can help increase the safety of the flight. There are literally thousands of factors that can be the cause of air turbulence, so avoidance is the best remedy. With the use of high-speed computing, flight travel is becoming safer every day. As we all know, air travel is safer than getting behind the wheel of a car!