FLEET UPDATE: Aerolineas Argentinas order for 20 737-887 changed to 9 737-887 and 11 737 MAX 8

Aerolineas Argentinas announced on 19Dec16 that it had negotiated with Boeing to change its October 2013 order for twenty 737-887's to nine 737-887's and eleven 737 MAX 8's.  The original order called for deliveries to take place between October 2016 and 2018 with three 737-887's already having been delivered in the latter part of 2016.  Up to three of the six remaining 737-800's to be delivered may also be converted to 737 MAX 8's, which would mean that future deliveries of this order might consist of only three 737-887's and fourteen 737 MAX 8's.

Aerolineas' first two 737 MAX 8's will be delivered in November and December 2017 with the early delivery being made possible by the deferral of an Alaska Airlines order.  Later 737 MAX 8's will be delivered at as yet undetermined dates.

The 737 MAX 8 is a new subtype of the 737 with two 737 MAX 8's currently flying in the type's test program.  Both of them are painted in the colors of Southwest Airlines, which will be the first airline to take delivery of the new type in the middle of 2017.  

Aerolineas Argentinas will be the first Latin American airline to place the 737 MAX 8 into service. COPA of Panama and GOL of Brazil are the other two Latin American airlines to have ordered the type and COPA was going to be the first to put it into service in 2018 until the Aerolineas order change took place.  

The 737-MAX 8 typically costs US$ 5 million more than the 737-800 but Aerolineas' agreement with Boeing was not disclosed and might be different. The MAX 8 burns 20% less fuel than early 737-800's and 14% less than the most recent versions with typical annual savings of US$ 800,000 per aircraft over the 800 at current fuel prices.  This better fuel economy translates to more range for the MAX 8 allowing it to fly longer missions.  Also, the MAX 8 is 40% less noisy.

The reduction in fuel consumption is mainly due to the MAX 8's CFM56 LEAP-1B new-generation engines, Scimitar winglets, which reduce drag more than conventional winglets, and some rear fuselage redesign.

Sources:

http://www.siscoma.com.ar/online/aviacion/2016/avn160929/avn-160929.html
http://www.siscoma.com.ar/online/aviacion/2016/avn161222/avn-161222.html
http://linea-ala.blogspot.com.ar/2016/10/boeing-737-887.html
http://www.sirchandler.com.ar/2016/12/aerolineas-argentinas-boeing-737-max/