The inaugural passenger airplane that truly embarked on commercial voyages and revolutionized air travel was the Douglas DC-3. While other early aircraft like the Boeing 247 were important milestones, the DC-3 stands out as the definitive game-changer in the history of passenger aviation due to its combination of innovation, reliability, and economic viability.

The journey to commercial passenger aviation was indeed a blend of visionary engineering and the culmination of advances in technology during the 1920s and 1930s. Prior to the DC-3, airlines mostly operated smaller, less efficient aircraft that were often uncomfortable and limited in range and capacity. The widespread demand for faster, safer, and more reliable transportation options, coupled with improvements in aerodynamics, metallurgy, and engine design, set the stage for a new era.

The Boeing 247, introduced in 1933, was revolutionary in its own right. Featuring an all-metal monoplane design, retractable landing gear, and variable-pitch propellers, it represented a significant leap forward from earlier biplanes and wood-and-fabric constructions. However, its relatively small passenger capacity (typically 10 people) limited its commercial impact.

This limitation was decisively overcome with the arrival of the Douglas DC-3 in 1935. The DC-3 offered comfort and speed for up to 21 passengers, making longer routes economically feasible for airlines. Its rugged construction and twin-engine design ensured reliability and safety, increasing public confidence during an era when many still viewed flying as risky and novel. Moreover, its operating costs were lower due to superior fuel efficiency and maintenance ease, which helped airlines make passenger flights profitable.

Economically, the 1930s were marked by the Great Depression, yet there remained a strong public appetite for rapid transit. The DC-3 perfectly balanced technological advances with economic practicality, enabling airlines to expand routes and schedules meaningfully. This expansion democratized air travel, slowly shifting it from a luxury sector to a more accessible mode of transportation.

The success of the DC-3 left an indelible legacy. It set design and operational standards that influenced decades of airliners. Its robustness meant many continued flying long after World War II, bridging the gap to the modern jet age. The DC-3 can rightly be called the pioneer that made commercial air travel truly viable and reshaped the global perception of flying from an adventurous novelty to an everyday necessity.

In sum, while the Boeing 247 broke important ground, the Douglas DC-3 stands as the true inaugural passenger airplane of commercial aviation. Its blend of engineering brilliance, economic timing, and operational success revolutionized air travel and paved the way for the modern industry we rely on today.