Nos. 12912, 12995. Argued February 1, 1960. Decided June 20, 1960. As Amended on Denial of Rehearing in No. 12912, August 26, 1960. Francis E. Marshall, Philadelphia, Pa. (James J. Davis, Davis, Marshall Crumlish, Philadelphia, Pa., on the brief), for petitioner Piasecki Aircraft Corp. Lowell Goerlich, Washington, D.C. (Ernest S. Wilson, Jr., Wilmington, Del., on the brief), for petitioners UAW-AFL-CIO and its Local 840. Allison W. Brown Jr., Washington, D.C. (Stuart Rothman, Gen. Counsel, Thomas