Unless there is evidence of some specific threat to which this is a response, this strikes me as open to legal challenge as being arbitrary and capricious, which is one standard for overturning an administrative action. I cannot think of a good reason for it and it seems designed to be punitive toward the airlines of countries that are not favored by the current administration. Moreover, if this is some kind of security action, it seems to be one that is easily circumvented by flying through a nation not subject to the ban.