Which of the following items are considered hazardous materials onboard?

The correct choice identifies flammable liquids, explosives, and toxic substances as hazardous materials onboard an aircraft. These materials are specifically regulated due to their potential to cause significant safety risks during flight. The presence of flammable liquids could lead to fires, while explosives might cause catastrophic events. Toxic substances pose health risks to passengers and crew, especially in confined spaces like an aircraft.

In the context of aviation safety, recognizing and managing these hazardous materials is crucial for preventing accidents and ensuring the well-being of everyone on board. Regulations from aviation authorities, such as the FAA and IATA, explicitly define these categories and guide what can be safely transported.

In contrast, food and beverages, pillows and blankets, and cushioning materials do not fall under this category as they typically do not pose a significant safety threat. Thus, they are permitted on aircraft without the same stringent regulations. This classification helps cabin crew focus on identifying and handling true hazards, maintaining overall safety during the flight.