The Boeing Co. marked the completion Wednesday of the first of what it hopes will be thousands of composite tail fins for its hot-selling 787 Dreamliner. The 33-foot-long tail fin is the largest structural piece of the 787 that Boeing is manufacturing. Its partners around the world are making the rest. .....snip... Making composite parts for Boeing jets is nothing new for Boeing's Composites Manufacturing Center. Workers here have been responsible for the composite tail fin and horizontal stabilizer of the 777 for about 13 years. Late last year, the unit delivered the 600th 777 composite empennage.