Higher level categories are created in the Conceptual Stage.
6. Conceptual: When the child has solved this problem we have the bases for a new higher level category. In the case of the car and plane etc., it is called transportation.
The amazing thing about these higher level categories is that unlike the percept where you can point to a member of the group, it is not so easy to do this with the concepts. Take for example the concept of Democracy. What is there to point to?