US$4.4 billion, the two companies announced Tuesday at the Singapore Airshow. The Indonesian carrier also acquired the right to purchase an additional 50 aircraft, Boeing said in a statement. With the new order for 56 planes, Lion Air will have 178 737-900ERs in its fleet. The single-aisle 737-900ER has a maximum capacity of 220 passengers in a single-class layout. The fuel-efficient planes have a range of 3,200 nautical miles (5,900 kilometers, 3,666 miles), Boeing said.