Final answer:
In 1991, Eastern Airlines, influenced by the deregulation of the industry, ended its operations after 64 years, making it the correct 'directional' airline referenced in the question.
Step-by-step explanation:
In 1991, one well-known airline, impacted by the changes following the Airline Deregulation Act of 1978, ceased operations after a storied presence in the aviation industry. This airline, known for its global reach and iconic status, was Eastern Airlines (option b). The deregulation act removed government control over airfares and schedules, leading to increased competition and several airline bankruptcies. While Pan American World Airways (Pan Am) is another prominent airline that eventually went bankrupt, this did not occur until December 1991, and Eastern Airlines is the correct answer according to the information provided.