DWDS is just plain wrong. *anreisen* does not specify the means of transportation at all, it could be by car, by rail, plane or ferry. It does imply a longer journey however, you wouldn't use it eg for a trip inside the same city.

The focus of *anreisen* is on reaching the destination, so it would be rather odd to apply it eg to travelling on a cruiseship, where the trip itself is more important than being transported to a destination. The destination also needs to be already in focus, ie if we take about Biden in the US, we can't suddenly take about how he "reist an" to Germany.