ub. L. No. 73-442, 48 Stat. 1185, 1188 (1934). As the Supreme Court noted, the RLA served as the model for the National Labor Relations Act. NLRBB v. Pennsylvania Greyhound Lines, 303 U.S. 261 (1938). See also NLEB v. Jones & Laughlin Steel Corp., 301 U.S. 1, 44 (1937); H. J. Heinz Co. v. NLRB, 311 U.S. 514, 524-525(1941)