Each executive -- Douglas M. Steenland of Northwest Airlines , Gerald Grinstein of Delta Air Lines and Glenn F. Tilton of United Airlines , a unit of UAL -- made the pledge .
Gerald Grinstein /business/person/company Delta Air Lines
DT NN : NNP NNP NNP IN NNP NNPS , NNP NNP IN NNP NNP NNPS CC NNP NNP NNP IN NNP NNPS , DT NN IN NNP : VBD DT NN .