American Airlines expects its first Boeing 787s to arrive about a year later than originally planned due to last year’s machinists’ strike at Boeing, according to an SEC filing issued by the Dallas-based airline yesterday. Last year the carrier signed a firm order for 42 Boeing 787-9s, the first of which it expected to arrive in 2012 and the last in 2018. Boeing expects to fly the first prototype late this spring, almost two years later than originally planned.

“Based on preliminary information received from Boeing on the impact of the overall Boeing 787 program delay to American’s delivery positions due to the strike in 2008, the company now believes the first of the initial 42 aircraft will be delivered during the second half of 2013,” said American in its filing. “The first of the 58 optional purchase rights aircraft would be delivered in the second half of 2016 based on the same preliminary information.”

Separately, American this week launched service with a pair of 737-800s, specially configured with two extra rows of new, thinner seats that give the airplanes a passenger capacity of 160, rather than 148. The 737-800s will burn 35-percent less fuel per seat mile than the MD-80s they replace, according to American. All told, the airline plans to take delivery of76 737-800s into early 2011 and it claims to hold financing commitments covering deliveries “well into the fourth quarter of 2010,” by which time it expects to have taken at least 56.