 As rival airlines convinced Congress that Pan Am would use its political clout to monopolize US air routes, the CAB repeatedly denied the airline permission to operate in the US, by growth or by a merger with another airline.Pan Am remained an American carrier operating international routes only (aside from Hawaii and Alaska).The last time Pan Am was permitted to merge with another airline prior to the deregulation of the US airline industry was in 1950, when it took over American Overseas Airlines from American Airlines.