A couple of months back I touched on the speculation in the industry about a future single-aisle product to replace the Boeing 737. I basically said don't believe the talk that a replacement is "just around the corner."

Well, some folks later told me they still think it's time for something new.

Well, believe me we have plenty of visionaries at Boeing, and they're working on amazing new stuff every day. And that includes looking down the road toward the next great thing in single-aisle aircraft.

But it's not going to happen in the immediate future. And the main reason is our Next-Generation 737 is in high demand. There's no pressure from airlines to find a successor to it. Unlike other industries, we don't replace our current products just for the sake of replacing them. A "new flavor" or a "fresh scent" don't work in our business.

Now, having said that, new airplanes are introduced only when we can demonstrate an improved "value proposition." In other words, some tangible reasons why a new airplane would fulfill an unmet need, or would lower costs and/or increase revenue vs. current products in the marketplace.

737 final assembly takes just 11 days at the factory in Renton, Washington.

This is usually driven by a set of breakthrough technologies. A perfect example of this is the 787 Dreamliner, with its dramatic improvements in efficiency, operating costs, and range.

Of course we're continuously studying new technologies and future products. We involve our customers and suppliers in that work. And it may be possible that the technologies going into the Dreamliner could achieve the same breakthroughs in a future single-aisle product.

It's just a matter of timing. Market timing and our timing. And right now the market isn't calling for it and we have no firm schedule for replacing our single-aisle product line.

Even so, let's talk about it. Both Airbus and Boeing are seeing a significant increase in demand for their existing single-aisle products. And the fact is few airlines are calling for an all-new airplane type.

The 737NG, 10 years newer than the A320, was first delivered in December 1997, and it's going strong. In fact, Boeing has delivered more than 1,700 Next-Generation 737s to about 150 operators.

So far in 2005 we have more than 450 orders for 737s and have added 9 new customers. This is already the single biggest year in terms of orders in the history of the 737 program. And we have a backlog of more than 1,000 of these airplanes right now.

The 737NG is popular with airlines because it has lower fuel consumption and operating costs than the competition, along with higher reliability. So the question is, what kind of breakthroughs would we need in order to add value to our single-aisle product line? What would cause airlines to demand an all-new single-aisle airplane?

Another delivery at Boeing Field. The Next-Generation 737 continues to be a best-seller with the world's airlines.

In the case of the Dreamliner, the 787 - compared with current airplanes in its segment - brings more than 20% lower fuel consumption and more than 10% lower operating cost. Strategically, those benefits are of huge value to airlines. The 787 also offers lower noise, faster speed, more comfort, and most importantly, more nonstop market access with its 2,000 nautical mile range improvement over current product offerings in its size.

So, it may boil down to breakthroughs in fuel consumption, operating costs, and other factors, along the lines of what we're seeing with the 787. Those breakthroughs would have to be so superior to today's airplanes that they would cause airlines to take on a new single-aisle airplane type along with the infrastructure cost associated with it.

Given all that, as is the case with all of our products, we're always looking toward the future. But the time for a new breed of single-aisle airplanes is still a ways off. Most likely you won't see a new single-aisle Boeing airplane enter into service for another ten years, give or take a few. The market will let us know when the time is right.