Boeing 787 models will be delivered on schedule next May despite delayed flight testing of passenger jet.
His comments at a Morgan Stanley conference in Dana Point, California, came six days after Boeing said the first test flight was pushed back to mid-November or mid-December due to complications with final assembly and finalizing flight-control software.
The delay will leave the company just five to six months before it is scheduled to deliver the first 787 to Japan's All Nippon Airways Co., or about half the time it took to test the 777 a decade ago.
McNerney told analysts the testing delay has simply eliminated the extra timing margin built into its plan.
"The plan has always been a five- to six-month (certification)" he said. "It's an aggressive plan, but it has substance to it."
The operation entails three shifts, 34 test pilots and only two engine types, compared with three for the 777, he explained. Advances in technology also have allowed for better flight tools to test aircraft, he said.
"Is there room for major glitches at this stage? The answer is no," McNerney said. "We're tight. ... We're down to the program having to go by the book."
McNerney said more should be known about timing of the first flight and any impact that could have on the delivery schedule by late October when Boeing holds a conference call to discuss third-quarter earnings.
"I'm disappointed that we've had a stutterstep," he said. "But it doesn't fundamentally change my view of Boeing's competitive position or where we're going to end up."
He also said Airbus' A350 "presents a challenge" to Boeing's long-range 777, raising the possibility the Chicago-based company will make modifications to its widebody. McNerney said the A350's debut could be as long as eight years from now.
"It gives us time to assess what the airplane is or isn't, can it meet the performance aspirations that it has, and it gives us time to respond," he said.
Boeing shares rose $2.42, or 2.5 percent, to $97.75 in afternoon trading, up 10 percent in 2007.