Cars are the de facto American transportation and what most cities are designed around. LAX is the 2nd biggest airport in the USA and has no direct rail connection either.
LAX was supposed to have a direct rail connection 20 years ago from the green line, but you can thank private parking lot owners for trenching up local opposition and the FAA for driving in the death knell on that effort. It does have a shuttle connection to the green line, and in the near future that shuttle will be replaced with a people mover.