Auto Layoffs Keep On Despite Overtime
Article on controversy in auto indus over fact that many workers are putting in heavy overtime while 28,000 others are still laid off; situation of overtime amid unemployment exists in many other production industries; mgt will often use overtime to get higher production rather than recalling laid-off workers or hiring new workers; Ford vp Sidney McKenna comments; plight of Ford employee Don Brown and former Ford employee Bob Burkes cited; illus (M)