I don't think your argument is polished enough to be worth pursuing vigorously. However, let's try to work with it point by point.
I know that there are a lot of kinds of paper, but the paper that I am asking in this question is the paper what we write on, print on - like a letter size paper or sketching paper.
Its nice you decided to narrow down the question a bit, sometime people won't to start with. However, its worth realizing that even writing paper is not always uniform in manufacture. For that matter, its probably worthwhile to consider what actually a cell wall is, and what actually paper is. Consider this: an aluminum ladder, won't fly like an aluminum airplane. Why not?
Considering that paper is made of cellulose, a cell wall of plants, I think air molecules can pass through paper, but only a little amount.
I think you need more than this. What is the structure of a cell wall? Does paper maintain such a structure?
1. Is there a scientific evident or source that can explain this question? I need scientific information regarding this question.
You could try to look it up in some secondary reference papers, trying to find some primary references. Then again, its all your idea, maybe you should write the paper. I can provide no primary reference the Earth is flat. Well, none that I'd want you to rely on. You can't blame me for that.
2. Also, is the diameter or overall size of air molecule bigger than water molecule?
3. Can air penetrate plant cell wall, or any kinds of cell membranes?
These are easily findable in references. This is what Borek: meant in his reply.
Thanks for your help in advance!!
Remember you wrote this when you respond to my questions.