I'm truly surprised at all the enthousiasts pooh-pooing this question Evidently, my question attracts a lot of aviation wisecracking.
Who is the aviation site intended for? We're not anticipating any member of the general public googling such questions, are we?
I understand your question, and I believe @Sanchises answered it well. (I haven't checked all the comments/answers.) An analogy for a young audience would be to compare a single sheet of paper (wrapping foil) and a stack of papers.
From the Help Center it reads:
Aviation Stack Exchange is a site for pilots, controllers, mechanics, and aviation enthusiasts.
So, your question is on-topic. But, what I'd do in your place is take in the comments, and consider editing the question to get better answers if the answers already aren't helpful to you.
Based on the comments, the way I'd rephrase the question would be:
How are aircraft fuselages designed and tested to ensure strength?
Or how do different materials compare? The Boeing 787 for instance uses carbon fiber for—IIRC—half the fuselage. On face value, that's plastic, like toys. But it isn't.
Note: Since there are answers already, you may consider posting a new question if any revisions would render the current answers obsolete.
I hope this answers your question. What I learnt here is in both writing questions and answers, the community here pushes for better questions and answers, that's why there's an edit button. You have no idea how many times I have edited my own posts. And I have benefited from that, and can only hope future readers will too.
Edit: It's about 2,500 edits for 500 posts. An average of 5 edits per post. Ignore about 2 per post for minor edits, that's 3 edits per post.
The StackExchange network works best for getting answers to (very) specific questions. This means that each question should include the goal of the question and the intended audience. Your original question contained neither, and was thus not well received.
I think the comments largely stemmed from the lack of this crucial context. Someone even took the effort of looking into your profile, to see if your background could help in identifying what exactly you wanted to know. Instead, they found that you have an engineering background, so one might ask, how can you not know basic pressure vessel formulas? Why would you directly relate the thickness of the exterior of a vehicle to the safety of the associated mode of transportation? To an engineer, that is almost akin to asking "Why are airplanes so safe, even though they have so many wheels?".
The comments, collectively speaking, tried to identify where your reasoning was so apparently misguided that you would ask this particular question, perhaps somewhat incredulous that an aerospace engineer would ask such a thing. Only then, it was discovered that the actual question read "How can I explain to the member of the general public that 1-2mm makes for safe air travel", so only then it became clear what the goal of the question was (how can I explain it to someone else), and what the intended audience was (someone who knows how to do engineering, but does not know how to explain this to laymen).
So, in conclusion, your original question did not reflect what you actually wanted to ask. As a result, the comment section contains some misunderstandings, which on the Internet are easily mistaken for "pooh-pooing" and "wisecracking" - perhaps due to cultural differences (being a Dutchman, I know many people would find my feedback rude, while I feel that gift-wrapping critique benefits no-one) or just due to the brevity and permanency of comments. My advice would be to assume good faith, and see all comments as people taking their time to help you answer your question. Only when you find people are insulting you personally or completely off-topic, you should flag comments; furthermore, once the comments have helped you rephrase your question, you may flag these comments as obsolete and forget they ever happened.
On a side note, this meta question title reads "What is the intended public for Aviation.SE", while the body asks about the content of comments. In response to the question title, I might add that you should ask questions that you want to have answered, not that you think others might want to know. From Help: Don't Ask: You should only ask practical, answerable questions based on actual problems that you face. So while the intended target of Aviation.SE includes the general public, you yourself are an expert, and do not need to ask all the questions the general public might ask.
