narrowbody කියන්නේ මොකක්ද???????
Narrow-body planes are usually up to 5 meters wide, wide-body are bigger than that. Narrow-bodies usually have one aisle, wide-bodies have two. The reason why there's this difference is pretty simple: for some routes with high demand you need bigger planes to transport more passengers, for others not.
Boeing 737 and 757, Airbus 320 and Embraer 170/190 are narrow-body jets. Most turbo-propelled aircraft are also narrow-bodies, e.g. Bombardier Q400, Saab 340 or ATR42/72. Narrow-body planes usually transport below 200 passengers
Planes like Boing 747, 767, 787 Dreamliner or Airbus 340, 350 and 380 are widebodies, with two aisles in economy class. B747 and A380 are also double-decker planes, meaning there are two passenger decks. Widebodies usually transport over 200 people; the biggest one - the A380 technically can in theory take up to ca. 850 passengers. Their routes are longer, like Singapore-Frankfurt, Los Angeles-New York or Warsaw-Beijing.