Hi boys & girls ---

Another design abstract problem. Let us say that we have a class called Airplane that's parent class is Vehicle. All Vehicles derived classes Move. How they move is quite different: Airplanes fly, Cars drive, and Rowboats are rowed. Which of the four approaches are taken:

1) The Vehicle superclass has Fly,Drive,and Row methods. The implementation of these methods is at either superclass or class level.

2) The Vehicle supports a Move method. The subclass defines Move as appropriate and returns a value indicating it flew,drove, or was rowed.

3) The subclasses have Fly, Drive, and Row methods as apppropriate; no Move or move specific methods are defined in the Vehicle superclass.

4) We have *no* Vehicle superclass and each subclass of Airplane, Rowboat, and Car is it's own superclass.

I currently strive for option 2 and used to use 4. Comments?