Final answer:
The pilot in command must possess a commercial pilot certificate to carry passengers for hire over 50 NM. Flight paths are regulated by the FAA to prevent collisions, requiring spacing of five miles laterally and 2,000 feet vertically between aircraft.
Step-by-step explanation:
To carry passengers for hire in an airplane on cross-country flights of more than 50 NM from the departure airport, the pilot in command is required to hold at least a commercial pilot certificate. This is formalized and regulated by aviation authorities such as the Federal Aviation Administration (FAA). Not only must pilots have the appropriate licensure, but the FAA also puts in place strict regulations regarding the traffic patterns of airplanes to ensure safety. This involves maintaining set distances between aircraft in-flight, similar to how particles like electrons are restricted in their positions in quantum mechanics.
Regarding the avoidance of collisions, the FAA mandates that commercial airplanes must keep a distance of five miles from another plane flying at the same altitude and maintain a vertical separation of 2,000 feet above and below another aircraft, or 1,000 feet if flying below 29,000 feet. These safety precautions, along with other tools such as radar and air traffic control communications, allow many planes to fly simultaneously without the risk of running into each other.