Final answer:
Customs agents are not a resource for an airline, while crew, passengers, and airplanes are.
Step-by-step explanation:
In the context of an airline, customs agents are not a resource for the airline. Customs agents are government officials who work at airports to enforce customs regulations and ensure that items entering or leaving a country comply with the applicable laws and regulations. While customs agents play an important role in managing and monitoring the flow of goods and people, they are not directly a resource for airlines themselves.
On the other hand, crew, passengers, and airplanes are all resources for an airline:
- Crew: The crew includes pilots, flight attendants, and other staff members who operate and manage the flights. They are essential for ensuring the safe and efficient operation of the airline.
- Passengers: Passengers are the customers of the airline who purchase tickets and utilize the services provided. They generate revenue for the airline.
- Airplanes: Airplanes are the physical assets that airlines use to transport passengers and cargo. They are the most critical resource for an airline.