Airline Etiquette could be subdivided into 2 main sections

On the Ground In the Air

On the Ground would include etiquette of baggage handling, checking in, airport lounges etc

In the Air would include getting on the plane, stowing luggage, reclining seats, using facilities etc

My particular interest is in reclining seats. I see many comments that reclining seats is 'rude'. I may be wrong but it appears that women and inexperienced travelers are more likely to take this view, whereas experienced travelers and/or men take the opposite view.

Today, in our Western Society, space is still a luxury and a commodity.  Proxemics and hapics(space and touch) on an airplane can easily violate another's personal territory.  In airline parlance, the anthropometric data shows what really matters are the width at the shoulder level.  On a 737-800, a 1st class seat's width is 20.5 inches and varying 17.01 inches in coach.  This small space screams at its occupants to please respect your seat-mate's by avoiding poor hygeine, excessive alcohol, hogging the arm-rest and of course, laptop spying.  You can refer to for translation of each airline and its fleet for the seat's comfort, width, depth, safety and leg room.

Another seat irritation is when its occupant uses the person ahead seat and head rest as an apparatus for rising.

My personal rules would be that seat reclining is ok when -

- On any evening flight (e.g. after 6pm) - On any flight 3 hours or over (i.e. long and boring)

It would not be ok when (i.e. you can do it but should ask first behind you if its ok, and/or accede to any request to raise seat) -

- daytime flight less than 3 hours (suck it up!) - person behind has a child in lap (special rules for kids) - person behind is handicapped and requires extra space (not their fault)