Which of the following leaders is best known as a visionary?

Billy Mitchell is best known as a visionary leader due to his forward-thinking ideas regarding military aviation and the future of air power. He was an early advocate for the importance of air force capabilities, predicting that air power would become a crucial component of military strategy. His vision included the potential for aircraft to change the landscape of warfare, which was not widely accepted during his time. Mitchell's ideas laid the groundwork for the establishment of an independent air service, influencing future generations of military leaders and aviation strategists.

In contrast, while John F. Kennedy and Martin Luther King Jr. were also visionary in their own rights, their visions were primarily focused on civil rights and national leadership within a political and social context rather than specifically on aviation. Anne Sullivan was an educational pioneer, best known for her work with Helen Keller, but her influence does not directly connect to the visionary role associated with military strategy and technology like Mitchell's. Each of these leaders had significant impact, but Billy Mitchell's contributions are particularly highlighted in the realm of visionary thinking in aviation.