Just like models of homes and buildings, miniature models of means of transport are useful for showing a project that is yet to be completed on a proper scale. For example, it would allow us to show the advantages of building a rail infrastructure in a city. We can also study the impact of a new model for a make of cars, or even produce prototypes of spacecraft and important vehicles such as fire engines. It is especially important to create a mock-up of the latter two before they are built, to prevent any errors in the final model.
These types of models are also used in other fields. In the military, soldiers learn about the actions that will be taken on the battlefield in the most realistic way possible, in a small-scale representation. It is also very common to use these prototypes in filmmaking; with camera tricks and close-ups they manage to create the atmosphere of a huge city in a space that only actually measures two square metres.