Which of these is NOT a requirement for flight into Mexico?

When considering the requirements for flight into Mexico, third-party insurance is not mandated for entry into the country, making it the correct choice for this question. In many cases, while flying into Mexico, third-party insurance might be highly recommended and is often necessary for safe operations or to satisfy a pilot’s personal requirements, it does not constitute an official entry requirement set by Mexican authorities. Therefore, a pilot can technically enter Mexico without presenting proof of third-party insurance.

On the other hand, valid radio operator certification is crucial as it ensures that the pilot can effectively communicate with air traffic control or other aircraft while operating in Mexican airspace. An IFR flight plan is essential for pilots operating under Instrument Flight Rules, allowing them to navigate safely through controlled airspace. Advising customs is also a requirement, ensuring compliance with immigration and customs protocols upon entering the country. Each of these components is strictly enforced and necessary for safe and legal operations within Mexican airspace.