The Boeing 737 series is the No.1 selling airliner in the world with over 5,600 aircarft built since production commenced in 1968. On average,Boeing 737 will take-off or land every 5 seconds around the world.The Boeing 737-800 is part of the ‘Next generation’ Series and is bigger, more efficient and more advanced than earlier models. It is mainly use in the low cost airline . Such as Nok Air and Thai lion Air.