A few days ago, Richard Russell, a 29 year old airline ground employee, got in a 76 seat commercial aircraft and took off from a crowded airport. Many people expressed surprise that he was able to accomplish this feat given the complexity of a modern commercial aircraft, noting that even starting the engines is a multistep process. In addition, he showed a fair amount of skill in flying the aircraft. Despite this, it appears he had no training in commercial multiengine aircraft and little, if any, formal pilot training.
In this instance, the troubled young man may have been suicidal, but fortunately, he was not murderous. After his joyride in the aircraft, it appears he intentionally crashed the plane into an uninhabited area. But what if his intentions had been different? Once he was airborne, it would have been a simple task for him to have crashed the plane, and its full load of fuel, into the terminal or another aircraft full of passengers. During a busy travel day, the potential loss of life would be staggering.