models.py

from polymorphic.models import PolymorphicModel


class Drive(PolymorphicModel):
    name = models.CharField(max_length=255)

    def __str__(self):
        return self.name


class TwoWheelDrive(Drive):
    pass


class FourWheelDrive(Drive):
    pass



class CarModel(models.Model):
    name = models.CharField(max_length=255)
    drive = models.ManyToManyField(Drive, related_name="carmodels")

    def __str__(self):
        return self.name