What was Eugene Ely's major achievement?

Eugene Ely's major achievement was piloting the first successful takeoff from a ship, which took place in 1910. This event marked a significant milestone in aviation history, as it demonstrated the potential for naval aviation and paved the way for future developments in aircraft carrier operations. Ely's successful takeoff from the USS Birmingham using a Curtiss biplane illustrated not only the capabilities of early aircraft but also established a foundation for integrating aviation into naval warfare. This accomplishment was crucial in leading to the development of dedicated aircraft carriers and the evolution of naval tactics.

The other options relate to advancements and innovations in naval aviation, but they occurred after Ely's pioneering flight. The design of angled flight decks and the development of Vertical Take-Off and Landing (VTOL) technology, as well as the handling of nuclear-powered aircraft carriers, came much later and were built upon the foundational work that figures like Ely started.