What major factor differentiates narrow-body and wide-body aircraft?

The primary factor that differentiates narrow-body and wide-body aircraft is indeed the number of passenger seats and the overall width of the aircraft. Narrow-body aircraft are typically designed to accommodate a smaller number of passengers, often ranging from around 100 to 200 seats, and feature a single aisle, allowing for a narrower fuselage. In contrast, wide-body aircraft boast a larger passenger capacity, often exceeding 200 seats, and are characterized by their two aisles and wider fuselage, which enables more spacious seating arrangements and additional amenities.

This distinction is crucial in the aviation industry as it influences the design, operational use, and market segment of the aircraft. For example, narrow-body jets are commonly used for short to medium-haul flights, while wide-body aircraft are preferred for long-haul routes due to their ability to carry more passengers and cargo over greater distances.

The other factors mentioned, such as engine type and location, range of the aircraft, and wing configuration, may vary between individual models within both narrow and wide-body categories but are not definitive characteristics that separate the two classes of aircraft in the same way that fuselage width and passenger capacity do.