Excluding some charges, American said net profit was $1.5 billion, compared with $681 million a year earlier, before the company had merged with US Airways.
American also plans $2.8 billion in payments on debt and aircraft leases.
"It is hard to believe that less than eight months ago, American was in bankruptcy, yet today, we are reporting record profits, repaying debt, making additional pension contributions, and declaring dividends to shareholders," chief executive officer Doug Parker said. "Performance like this proves we are on the right track and gives us confidence as we move forward."
United announced its $1 billion buyback would be spread over the next three years. Revenue was up 3.3 percent to $10.3 billion.
United chief executive Jeff Smisek described the performance as "solid progress." United was the only major U.S. carrier to report a loss in the first quarter.
With industry consolidation and the recent mergers of Delta and Northwest, United and Continental, Southwest and Air Tran, and American and US Airways, the remaining airlines can control capacity - the number of seats and flights - and keep airfares stable.
Southwest Airlines, Philadelphia's second-busiest carrier, reported net income of $465 million, or 67 cents per share, compared with $224 million, or 31 cents a share, a year earlier. Based on the favorable earnings, management said it would award each Southwest employee a one-time $200 cash bonus.
"We had high conviction Southwest would report better-than-expected results, and they delivered all that and more," analyst Helane Becker of Cowen & Co. said in a client note. "The outlook remains quite strong, especially on the cost side."
JetBlue Airways, which flies to Boston from Philadelphia, announced its 17th consecutive quarter of profitability. The airline reported revenue of $1.5 billion during April, May, and June, with net income of $61 million, excluding some items, up from $36 million during the same period last year.
"We saw improved profitability across our network," said JetBlue chief executive Dave Barger, "reflecting the success of ongoing efforts to adapt our products and services to meet our customers' ever-changing needs."