But the marketing agreement between Northwest and KLM offers an example of how consumers benefit from such relationships.

Talks between Northwest and the union are continuing.

But talks between American and Northwest stalled earlier this year after Northwest demanded a high price and showed little interest in selling.

"Between United and Northwest, we are proving to the Russians that this is a viable operation."

A main sticking point in the negotiations between Northwest and the pilots, according to both sides, was the pilots' pay.

In any such alliance as the one planned between Northwest and Continental, there will be disputes.

"The code share between Northwest and Continental has worked well as both networks, for the most part, are complementary," Mr. Linenberg said.

Among the domestic carriers, probably the best-known alliance is between Continental and Northwest, which have been partners since 1998.

It is too late to block anti-competitive mergers, notably the merger between Northwest and Republic, that sharply reduced the number of carriers in regional markets.

The route maps are a cure for insomnia unless you catch wind of a fare war like the one between United and Northwest last month.