Re: Airlines have a problem thatcustomers can't fit in the seats anymore
I find the sentence you quoted about the airline problem to be rather unnatural. I would have said "Airlines have a problem, in that customers ..." or "Airlines have a problem, which is that customers can't fit ..." It may be that the quote is a direct transcript of what someone said in an interview. If that is the case, then you have to remember that people don't always speak grammatically when it's not scripted.
Originally Posted by optimistic pessimist
Your suggested sentence is not natural. For a start, I wouldn't say "I have suffered a problem", either "I had a problem" or "I suffered from ..."
Remember - correct capitalisation, punctuation and spacing make posts much easier to read.