United, US Airways May Give It Another Go

Of course, the difficulty of merging pilot seniority lists would make addressing global climate change appear, by comparison, to be a weekend diversion. Already, a bitter election has led the 5,238 US Airways pilots to split from the Air Line Pilots Association, which had represented them for 57 years. Now add 7,000 United pilots, who remain ALPA members and who are dedicated -- as are all pilots -- to retaining their seniority.

Also, the route synergies, while positive, raise some questions. In New York, United would gain access to LaGuardia, one of the country's most important airports, but not to Kennedy or Newark, the international airports. Star Alliance would still lack a hub in the world's largest travel market, making the Lufthansa investment in JetBlue(JBLU Quote) seem all the more worthwhile, even if the final shape of their link-up is not yet clear.

The pressure on Philadelphia's cramped airport, where US Airways has a hub, should ease because of United's hub at Washington's Dulles. But in the nation's capital, a merger would reopen the question of whether one airline should dominate at both Dulles and Reagan National.

On the positive side, it should be easy to make the case to regulators that US Airways on its own will never achieve the international presence sufficient to sustain a legacy carrier in the face of rising fuel costs. Additionally, there is little overlap between the two carriers' route systems.