Hazards Aircraft must take off and land without incident. Because airspace in some areas is very crowded, sophisticated electronic gear helps fly the aircraft and control traffic in the highways of the air. Aviation hazards have changed with aircraft scale, speed, and altitude. Structural loads are greater, requiring exotic metals, like fiber-reinforced titanium. Structures face expansion and contraction from repeated loading, pressurization and depressurization, and thermal expansion and shrinkage. .