* Structural problems. Early aircraft were often built with lightweight materials, such as wood and canvas, which were not very strong. This made them susceptible to damage from gunfire and even minor accidents.
* Engine problems. The engines of early aircraft were also unreliable. They were prone to overheating, catching fire, and even exploding.
* Lack of instruments. Early aircraft did not have many of the instruments that are standard today, such as altimeters, airspeed indicators, and compasses. This made it difficult for pilots to fly safely, especially in bad weather.
* Inexperienced pilots. Many of the pilots who flew in World War I were inexperienced. They did not have the training or experience to fly these early aircraft safely.
As a result of these factors, airplanes were very dangerous to fly in World War I. It is estimated that as many as 50,000 pilots were killed during the war.
Despite the dangers, airplanes played an important role in World War I. They were used for reconnaissance, bombing, and even dogfighting. As the war progressed, airplanes became more reliable and safer to fly. By the end of the war, airplanes had become a major part of military operations.