all improvements implemented, the resulting aircraft would have a maximum takeoff weight of greater than . The company slowly introduced aspects of Ozark over time. An engine Performance Improvement Package resulted in a 2% lower fuel burn. Boeing also improved the tail fuel tank's function and improved the flight management software. Aircraft produced beginning in 2014 weigh less than the first 747-8 coming off the production line and burn 3.5% less fuel. Other improvements include revised fairings next to the tail and wing-to-body-fairings. The chevrons on the trailing edge of the GEnx-2B nacelle were made thinner. Boeing hoped that these improvements, which benefit both the passenger and freighter version, would help improve sales. Boeing has since updated the incremental improvements planned for the , which include increasing the maximum takeoff weight to , strengthening the main landing gear and increasing the aircraft's full-payload range to . Sales prospects In early 2014, the director-general of the International Air Transport Association noted that slower economic growth, following the Great Recession of 2008, had led to lower demand for air freighters. The world's air cargo fleet in 2012 was smaller than it was in 2003. However, the proportion of very large freighters in that fleet has increased, and Boeing's dominant position in large, fuel-efficient freighters has offered the company an opportunity to protect its market share and its product line despite the market weakness. Demand has been chiefly for the 747-8F, which accounts for the majority of 747-8 aircraft ordered. The large capacity of the 747-8 is an advantage for the freighter version, not the passenger version. Moreover, the freighter has no direct competitor, as Airbus' competing A380 freighter version was canceled during development. Airlines including Emirates and British Airways considered ordering the passenger version, but opted to purchase the Airbus A380 instead. In 2013, Arik Air converted its order for two 747-8s to two 777-300ERs. At the 2013 Paris Air Show, Korean Air agreed to order five 747-8 passenger versions, in addition to five ordered in 2009. Korean Air and Boeing finalized the new -8 order in October 2013. The overall demand for the 747-8 turned out to be below Boeing's initial projections as well, which led to several reductions in production rate. Production was initially decreased from 2 to 1.75 aircraft per month in April 2013 and then reduced further to 1.5 aircraft per month in October 2013. On June 25,