According to the FAA, which characteristic is NOT one of the seven essential traits airports should have?

The trait that is not considered one of the seven essential characteristics of airports, according to the FAA, is the requirement to be located within 20 miles of major cities. While proximity to urban centers can enhance accessibility and passenger convenience, it is not a mandated characteristic for all airports. The key traits typically emphasize operational functionality, safety, adaptability to technological advancements, and consistent maintenance, among other essential attributes.

The options referencing accommodating new aircraft types, maintaining design standards, and remaining open permanently align with the FAA's focus on ensuring that airports can effectively support current and future aviation needs, operate safely, and be resilient over time. Each of these aspects plays a significant role in the overarching goals of airport development and management as established by regulatory guidelines.