To see or sleep on an inflatable bed refers to a temporary situation or relationship. You are not in it for the long term.
Dreaming that you are inflating an air mattress indicates that you are putting too much effort into a one-sided relationship. You are putting in more than you are getting back.
If you dream of blowing up the inflatable mattress in one breath, then it means that you are overly ambitious. You are taking on more than you can handle.