The cfi idea is not a bad way to go. Try it part time while staying in your field for now. Do you have any flight time or are you on the outside looking in thinking that would be great? Its a worthwhile profession if your heart is in it, but at 40 its a lot tougher to survive on tuna and peanut butter compared to 20. Realistically the big guys are probably out of the question for you so you need to consider that your career will probably be at a regional. There will always be good times and bad times in the industry-now is obviously not a good one.