What typically marks the upper limit of Class G airspace?

Class G airspace, also known as uncontrolled airspace, extends from the surface of the earth to the base of the overlying controlled airspace. This characteristic is crucial for understanding airspace management and the transition between controlled and uncontrolled environments.

The base of the overlying controlled airspace can vary but is determined by the specific airspace structure in that area. For example, Class E airspace typically starts at a defined altitude, which can be at various levels such as 1,200 feet AGL, 700 feet AGL, or for certain locations, at the surface. This means that Class G airspace will exist below these levels until the airspace changes to a higher classification.

While the surface of the earth marks the lower limit of Class G airspace, it is not the upper limit. Additionally, options such as 2,500 feet AGL and 10,000 feet AGL reflect specific altitudes that could fall within Class G but do not define its upper limit since the airspace can extend much higher depending on the presence of controlled airspace above it. Therefore, defining the upper limit of Class G airspace accurately as the base of overlying controlled airspace is essential for safe navigation and airspace understanding.