Not only are the air bubbles insulative on their own, they are small enough that they don't develop convection paths within them (this is a problem with double/triple glazed windows
or walls with large air spaces). Products like Reflectix have both the built-in air gap (heat transfer by air conduction is not efficient and therefore is insulative), plus the reflective surfaces on both sides.
The trick to controlling condensation is to drive it to where it can be handled, like window surface that drains to outside vs back sides of window frames where it builds up unseen.
For example, my Scamp's front window was getting condensation that was running down inside and causing problems on the front upper bunk because there is no window drain -- I glued some closed cell foam to the underside of the gravel guard so the window was insulated from the outside and then put up curtains to restrict air movement of moist air into that area. I crack the roof vent to allow the warmest (most moisture-laden) air to vent out.
You can't not have water vapor/condensation because merely breathing puts it in the air; what you can do is deal with the vapor before it becomes a problem in terms of mildew, etc.