When you warm up for a Cardio Class workout is it safe to stretch or not and what types of stretching do you use?

I too am old school when it comes to warming up and stretching. In aerobic/cardio dance classes the warm up is used to introduce any new choreography that you might be using and to increase blood and oxygen flow to the major muscle groups and joints. I also incorporate dynamic stretching in the beginning and then immediately after the cardio workout. I work with multiple generations and this sytem has served to avoid injury and to help participants understand the benefits of including flexibilty in their workout regime.