What is a primary cause of delays at airports, accounting for 66% of them?

Weather is a primary cause of delays at airports, accounting for a significant portion of overall flight disruptions. Weather conditions can lead to reduced visibility, low cloud cover, severe storms, or high winds, all of which can hinder aircraft operations and limit the airport's ability to maintain its usual flight schedule. Delays caused by weather can affect both takeoffs and landings and can cascade throughout the entire day’s flight schedule, impacting many passengers.

While other factors, such as technical issues, airport capacity, and passenger volume, do play a role in causing delays, they generally represent a smaller percentage of the total. For example, technical issues may refer to problems with the aircraft but only affect individual flights. Airport capacity can lead to delays, particularly during peak times, but it's often the weather that creates the most widespread and unpredictable disruptions at airports.