A narrow-body aircraft (also known as a single aisle aircraft) is an airliner with a fuselage aircraft cabin width typically of 3 to 4 metres (10 to 13 ft), and airline seat arranged 2 to 6 abreast along a single aisle. Narrow-body aircraft with a range not allowing transatlantic or transcontinental flights are commonly known as regional airliners.
In contrast, a wide-body aircraft is a larger airliner and is usually configured with multiple travel classes with a fuselage diameter of 5 to 7 metres (16 to 20 ft) and twin aisles. Passengers are usually seated 7 to 10 abreast. For comparison, typical wide-body aircraft can accommodate between 200 and 600 passengers, while the largest narrow-body aircraft currently in widespread service (the Boeing 757–300) carries a maximum of about 250 – 275.