What organization formulates the regulations that govern all US airlines?

The organization that formulates the regulations governing all U.S. airlines is the Federal Aviation Administration (FAA). The FAA is responsible for regulating civil aviation to promote safety and ensure compliance with the Federal Aviation Regulations (FARs). This includes overseeing the certification of airlines, pilots, and aircraft, as well as establishing safety standards and procedures that all commercial carriers must follow.

In the context of aviation regulations, the FAA plays a crucial role in maintaining the safety, security, and efficiency of the U.S. airspace system. It conducts research, develops regulations, and provides guidance to airlines and aviation professionals, ensuring that they adhere to the highest safety standards.

The other options listed, such as the National Transportation Safety Board (NTSB), the Department of Transportation (DOT), and the Aviation Safety Bureau, play important roles in the aviation industry but do not specifically formulate regulations for U.S. airlines. The NTSB focuses primarily on investigating aviation accidents, the DOT oversees broader transport policy, and the Aviation Safety Bureau does not exist as a regulatory authority within the U.S. aviation system. Therefore, the FAA's role in formulating and enforcing regulations makes it the correct choice for this question.