Updated

Continental Airlines Inc. and UAL Corp.'s United Airlines are expected to announce Monday that they are merging to form the world's largest airline by traffic, people familiar with the matter said.

The United board is meeting Friday, while Continental's board is meeting Friday and Sunday to discuss the deal, these people said.

These people cautioned that negotiations could fall apart at the last minute as they did in 2008, when Continental backed away. But after a hiccup over pricing the transaction, the talks appear to be on track, they said.

United is in a much different position than two years ago. Earlier this week, United narrowed its first-quarter loss to $82 million, compared with a year-earlier loss of $382 million. Revenue rose by 15 percent, to $4.2 billion.

Those earnings led United to believe it had more leverage in the talks, which were at an impasse this past weekend over the share-price ratio used in a stock-swap transaction.

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