The Chicago-based aircraft maker expects to roll out the first 737 MAX before the end of 2015, fly it in early 2016 and deliver it to customers on time beginning in the third quarter of 2017, Boeing spokesman Doug Alder said in a statement. On Thursday, The Wall Street Journal reported concern among industry executives that the process could be slowed because of problems at GKN producing the jetliner’s engine thrust reversers. A spokesman for GKN declined to comment on Friday.