Which type of aircraft is classified as a double-decker passenger airliner?

The Airbus A380 is classified as a double-decker passenger airliner due to its unique design that features two full-length passenger decks. This allows for a higher seating capacity compared to other aircraft, providing airlines with the ability to carry more passengers on long-haul flights efficiently. The A380's design enhances the passenger experience by offering spacious cabins and various amenities across its two levels.

In contrast, while the Boeing 747 typically has a partial upper deck, it is not considered a true double-decker as the majority of its passenger capacity is on the main deck. The Airbus 737 and Embraer 190 are narrow-body aircraft, primarily designed for short- to medium-haul flights, with only a single deck. Therefore, the design of the A380 stands out in the aviation industry as the largest and most recognized double-decker passenger airliner.