A more thorough explanation:

Definition: Navigable airspace refers to the area above the legally established minimum flight altitudes, including the space needed to ensure safe takeoffs and landings of aircraft.

For example, when a plane takes off or lands, it needs a certain amount of space above the ground to do so safely. This space is considered navigable airspace. It is also the airspace that planes fly in when they are traveling from one place to another.

In international law, each country has its own national airspace, which includes the airspace above its territory, internal waters, and territorial sea. Foreign aircraft are not allowed to fly through this airspace without permission from the country.

Overall, navigable airspace is the area where planes can safely fly and operate, and it is important for ensuring the safety of air travel.