Select ForeignKey field in form ChoiceField
Perhaps you're looking for ModelChoiceField
?
To use it, you would write something like:
class VehicleForm(forms.Form): series = ModelChoiceField(queryset=Series.objects.all()) # Or whatever query you'd like
Then do the same for the other fields.
Of course, you would probably use a ModelForm but that's just an example. Is that what you're looking for?