Which statement correctly describes the two airport types?

• A. Controlled airports have a staffed tower; uncontrolled airports do not.
• B. Uncontrolled airports have a staffed tower.
• C. All airports are controlled.
• D. Controlled airports are in international airspace.

Answer: (A)

The core idea here is the difference in who provides air traffic control at the airport. Controlled airports have an air traffic control tower that is staffed to manage runway operations, sequencing arrivals and departures, and coordinating aircraft on the ground. Uncontrolled airports do not have a staffed tower, so pilots use non-towered procedures, self-announce on a common frequency, and coordinate visually with other traffic.

This makes the described statement the best: it accurately contrasts the presence of a staffed tower with the absence of one, which is the defining distinction between controlled and uncontrolled airports in typical practice.

The other ideas don’t fit as well: an uncontrolled airport does not have a staffed tower; not all airports are controlled—there are many non-towered fields; and being controlled is not about being in international airspace—the status relates to ATC services at the airport, not the international designation of the surrounding airspace.