This Airline Wins the Most From 'Open Skies'

Still, yields at Heathrow are higher than at Amsterdam, Frankfurt and Paris, the other key European hubs, Koster said, noting: "London is the financial capital of Europe."

In China, where liberalization is occurring more slowly, Northwest's growth will likely be ahead of the curve.

"We probably have the most experience in Asia, where we just celebrated our 60th year anniversary, and we are probably are going to be the most ambitious about expanding in Asia," Liu said. "We are deep in the heart of trying to understand how much demand there is to and from the secondary cities in China."

The arrival of Boeing 787s, starting in the first half of 2009, will trigger Northwest's China expansion, Liu said. The two countries' May agreement provides limited access to Beijing, Shanghai and Guangzhou, along with easier access to most other cities.

Determining the level of demand in those cities is a problem, because data is practically nonexistent. Much travel occurs "off the grid," Liu says.

Industry consultant Mike Boyd, who regularly analyzes aviation opportunities in China, says: "There are no metrics to use, and there is a whole lot we don't know. We don't know much about travel patterns. We don't know about how the air space is managed.

"But there is a lot of economic growth, and there is a lot of traffic, and Northwest is sitting in the catbird seat," he said. "They have access to many of the places where China invests in the U.S., they have a Tokyo hub, and they understand the value that brings them."