Nos. 21129, 21226. Argued March 15, 1968. Decided July 2, 1968. Petition for Rehearing Denied October 9, 1968. Mr. Edward L. Carey, Washington, D.C., with whom Messrs. Harrison Combs and Willard P. Owens, Washington, D.C., were on the brief, for petitioners in No. 21,129 and intervenors in No. 21,226. Mr. Guy Farmer, Washington, D.C., with whom Mr. John A. McGuinn, Washington, D.C., was on the brief, for respondent in No. 21,226. Mr. Glen M. Bendixsen, Atty., National Labor Relations Board, with