Becoming licensed to fly is very similar to learning how to drive a truck; you do not need a bachelor's degree to qualify. However, as the industry evolved and competition for captains' slots increased, airlines and other employers increasingly started demanding a relevant degree for such a responsible position.
Today, a student with an eye on an airline career will typically gain their private pilot's license and advanced ratings at a flight school partnered with a local university. In parallel, they will then study physics, mathematics, aviation management, and air law in an academic environment. Once graduated, each is supposed to be capable of both piloting their designated aircraft and performing general managerial duties within the airline industry.