CHICAGO — The Boeing Co. said Thursday that it delivered 181 commercial planes during the second quarter, a 7.1 percent increase from the same period a year ago.The deliveries included 124 next generation 737s, 30 787s, 24 777s, two 747s and one 767. It said it has delivered a total of 342 commercial planes so far this year.The Chicago company said its defense, space and security unit also saw gains. It delivered 45 planes or helicopters and two satellites. That’s up from the 31 planes and helicopters it delivered in the second quarter last year. Shares of the aircraft maker added 55 cents to $128.17 in morning trading Thursday.