List the types of airspace classifications in the United States.

The classification of airspace in the United States is designed to regulate the use of airspace for safety and efficiency. The correct answer identifies the six types of airspace classifications as Class A, B, C, D, E, and G.

Class A airspace is for high-altitude flights, primarily for IFR (Instrument Flight Rules) operations, where all flights must be conducted under instrument conditions. Class B airspace surrounds major airports and is designed to manage high-density air traffic, requiring an individual clearance from air traffic control (ATC) for entry. Class C airspace also involves airports with significant traffic, where communication with ATC is required but does not require explicit permission like Class B. Class D airspace pertains to airport operations, typically surrounding smaller airports with an operating control tower, where pilots must establish communication with ATC prior to entry.

Class E airspace is typically designated for less busy areas, where IFR flights can occur, and is often used for instrument approaches and departures. Finally, Class G airspace is uncontrolled airspace, where pilots may operate without the need for communication with ATC under certain conditions.

This comprehensive classification system ensures organized use of the airspace, maintaining safety for all types of operations—from commercial airlines to