Which organization represents nearly 20,000 air traffic controllers and aviation safety professionals in the U.S.?

The organization that represents nearly 20,000 air traffic controllers and aviation safety professionals in the U.S. is NATCA, which stands for the National Air Traffic Controllers Association. This labor union specifically focuses on the interests of air traffic controllers and various other employees within the field of aviation safety. NATCA's roles include advocating for safe air traffic practices, negotiating working conditions, and ensuring that the voices of its members are heard in regulatory and legislative matters.

The other organizations listed have different focuses. NATA, which refers to the National Air Transportation Association, primarily advocates for general aviation service providers. ALPA, or the Air Line Pilots Association, represents airline pilots. AOPA, which stands for the Aircraft Owners and Pilots Association, focuses on the interests of general aviation pilots and aircraft owners. Understanding the specific mission and membership base of these organizations helps clarify why NATCA is the correct choice in this context.