Final answer:
The minimum altitude for an airplane flying over a congested area is 1,000 feet above the highest obstacle within a horizontal radius of 2,000 feet from the aircraft.
Step-by-step explanation:
The minimum altitude for an airplane flying over a congested area is determined by regulatory standards outlined by the Federal Aviation Administration. According to these standards, the minimum altitude for an airplane is 1,000 feet above the highest obstacle within a horizontal radius of 2,000 feet from the aircraft. This ensures the safety of the airplane and the people on the ground, as well as prevents any potential collisions with buildings or other obstacles.