Air mattress or plywood under foam mattress on sleep sofa?

I have never had to make our sofa into a bed as we have four bunks but I read this and thought it was a good idea. Cut a swimming noodle down the center and lay it in the divide between the sofa halves. Lay whatever you have decided upon on top of it. I love air mattresses when we are tent camping but like foam as you do not have to worry about it leaking.
And I would not expect my husband to sleep on it. That sounds like the worse in better or worse.