AIRLINES

Delta, American Lay Off Pilots: Delta Air Lines said it has laid off 136 pilots in a round of furloughs announced in March, and American Airlines said it plans to lay off up to 450 pilots. American said its layoffs will come between August and February. Delta said the pilots were furloughed effective Tuesday, and about 600 pilots in all will be let go by the fall. American Airlines employs 10,000 pilots, and Delta employs 9,400. Both carriers have been hit by the continuing recession in the world air travel business.