What was different about things like fashion and modes of transport and other aspects of US culture after WWII ended?
American culture changed in innumerable ways after the war.
As far as modes of transport go, there was a move towards much more use of cars and airplanes. Before the war, airplane travel hardly existed and trains were much more prevalent than cars. After the war, the advances in airplane technology led to the creation and expansion of passenger airlines. After the war, the building of new roads and the new-found prosperity led to a boom in automobiles.
As far as fashion went, the most different thing was that women started to dress in much fancier ways than they had. This is not at all surprising given that the years before had been full of poverty (Depression) or rationing (war).