What are common reasons for flight cancellations?

The most common reasons for flight cancellations include technical issues and weather conditions because these factors significantly impact the safety and feasibility of operating a flight. Technical issues may involve mechanical problems with the aircraft that require resolution before the flight can safely take off. On the other hand, weather conditions can include severe storms, heavy snowfall, or other adverse weather patterns that make it unsafe to fly. Airlines prioritize passenger safety and fulfill regulations that require them to cancel flights under such circumstances.

The other options do not encompass the broader range of factors that can lead to cancellations. While security issues can certainly lead to a cancellation, they are less common compared to technical and weather-related challenges. Staffing issues can also affect flight operations, but they tend to be less frequent than the other two primary reasons. Passenger complaints, while important to address for customer service, typically do not lead to cancellations unless they escalate to significantly impact flight operations or security. Therefore, the correct answer highlights two of the most frequent and impactful reasons for flight cancellations.