The award to American is the latest chapter in a bitter dispute that crippled the country's second-largest airline this winter.
United, the second-largest airline behind American, filed for bankruptcy protection in December 2002.
Under the pilots' bid, United's 70,000 employees could end up owning as much as 75 percent of the nation's second-largest airline.
But the next round of political warfare over United, the nation's second-largest airline, is certain to begin almost immediately.
The announcement, which came after a meeting of the company's board, seemed to indicate that the nation's second-largest airline might well be for sale.
American, the nation's second-largest airline after United Airlines, has already agreed to the proposal.
Both business and leisure travelers are worried about United, the nation's second-largest airline.
The bankruptcy filing gives United, the world's second-largest airline, more time to look for cures to its ills.
United, the world's second-largest airline, would then file for bankruptcy protection shortly afterward.
United is the second-largest domestic airline after American, which recently set $300 million in cost savings as its goal for 1993.