Every living person, from infants to older people, gets affected by internal and external factors. There are numerous researches and writings related to humans and these various factors. Human factors are recognized since the start of the human race. The awareness of the impacts of our environment is not new to humans. The focus in this chapter is upon those factors which can create an impact on aircraft mechanisms and air traffic controllers. These factors include human, psychological, work conditions, training, health conditions, environment, societal, and training. These factors must be quality controlled to minimize the errors in the critical domain of air traffic. A reduction in the number of errors will allow the performance to be higher and lowers the chances of fatal accidents.