Air travel's advantages put long distance intercity railroad travel and bus lines under pressure, with most of the latter having withered away, whilst the former is still protected under nationalization through the continuing existence of Amtrak.
As vantaxes da viaxe en avión metéronlle presión aos trens e autobuses de longa distancia, perdendo estes últimos gran parte do seu negocio, mentres que o ferrocarril está aínda protexido pola nacionalización grazas á existencia de Amtrak.