Still, no one denies that a respectful yet pronounced division separated engineers on the commercial side of the Boeing ledger from those on the military arm.
The evidence that both sides in fact play on the same team descended on St. Louis last week when a prototype of the Chicago-based aircraft maker's fuel-efficient, long range commercial aircraft, the Boeing 787, touched down on a runway at Lambert-St. Louis International Airport.
Dubbed the Dreamliner, the 787 is among the first collaborative efforts between the company's Seattle-based commercial engineering unit and their counterparts at the Defense, Space and Security division headquartered in Hazelwood.
Seattle aerospace analyst Scott Hamilton says Boeing's successful launch of the 787 testifies to the talent the St. Louis engineering corps brought to a project plagued by cost overruns and production glitches.
"They absolutely borrowed or stole engineers from Boeing defense as the problems got worse," said Hamilton. "So, yes, you had collaboration. But (the defense engineers) were the relief pitchers."
One reliever was Greg Busche, assigned in 2007 to manage the St. Louis Commercial Support Group
An engineer for 26 years at McDonnell Douglas and, after the 1996 merger of the two aerospace giants, Boeing, Busche was well-versed in in the design of the F/A-18 Super Hornet and the other fighter jets manufactured for U.S. and worldwide military customers.
The basic thrust of Busche's responsibilities remained the same.
But the challenge of moving from a 60-foot aircraft carrying a maximum of two pilots that's designed to land on aircraft carriers to the logistics of an 186-foot jumbo jet capable of transporting as many as 250 passengers up to 8,500 nautical miles required him to recalibrate his expertise.
Though the schematics of the retrospective aircraft vary greatly - the wingspan of the 787 is four times greater than that of a Super Hornet jet fighter and the commercial jet stands a full 40 feet higher - the basic principles of aerodynamics carried the day.
"It's kind of like speaking French and speaking German," said Busche. "You can say the same thing, but you say it in different ways."
Sinnett, the Seattle-based chief engineer on the project, concurs:
"How an engineer solves problems doesn't change no matter the domain," he said.
The commercial-defense division partnership born when Boeing combined forces with McDonnell Douglas resonated personally with Sinnett.
A St. Louis native, Sinnett traces his roots as an "airplane nut" to his father - a senior executive at McDonnell Douglas at the time of the merger.
The younger Sinnett began on the defense side of the business but moved to commercial engineering after re-locating to Seattle.
He acknowledges the corporate mandate for "One Boeing" took getting used to.
"It was not natural for us in the beginning," Sinnett said of the collaborative effort with the defense engineers. "The hard thing was remembering that we needed to tap a great enterprise."
In St. Louis, Busche and his team concentrated their efforts on the floor structure and structural design and analysis as Boeing struggled to rectify an estimated $2.5 billion in cost overruns and delays that set delivery of the first of the $200 million jetliners nearly three years behind schedule.
Hamilton blamed a fair share of the predicament on Boeing's decision to encumber the process by outsourcing portions of the project to vendors and suppliers spread across the globe.
"There were certainly too many cooks in this kitchen," the analyst said. "But it's not fair to say Boeing defense was one of those cooks."
The ongoing development of the P-8A Poseidon maritime surveillance aircraft and the KC-767 Tanker, both of which are based on the airframs of Boeing commercial jets, provides the company with further opportunity to hone the joint effort between its two divisions.
When all was said and done, Sinnett acknowledged the ability of the St. Louis-based engineers to identify and solve problems as they arose proved invaluable.
Boeing is filling orders totaling $178 billion for 870 additional 787s from 59 customers around the world.
At least one paying passenger will board more interested in the flight than his destination once Dreamliners begin materializing on U.S. commercial fleets.
"This is the first program I've ever worked on that I can actually fly," said Busche, the defense engineer. "I'm going to get a ticket and take a ride."