I don't travel a lot, however when I do - distances are literally insane!
My personal record was to cross Atlantic Ocean six times in one year (most often it is a flight from Australia to Europe and back). Some of the longest non-stop trips over the air lasted 15 to 16 hours (Australia - Emirates).
When somebody asks: "Hey, Nick. Does it shake in a plane?". I answer: "Yes, but there are particular spots where turbulence is really bad". In this short blog-post I will list top 3 areas where turbulence is the worst!
3. Turkey - Iraq border
Having over 20 flights over Turkey couple of times the wind on the border with Iraq was strong enough to wake up all passengers including myself.
Why? I suspect mountain surface near Erbil region creates conditions which magnify wind stream causing planes to shake for an hour or so.
2. Indonesia and Java Sea
When it comes to flying over the Asia, crossing of Malaysia and Indonesia is a compulsory route. This area is very infamous for its plane crash catastrophes including couple of Malaysian Airlines flights.
Every time Java Sea is coming on map info screen - I tighten my seatbelt and wait until we fly over. Mostly it happens due to substantial rain and storm activity, which creates strong wind ideal for plane being in turbulence zone.
1. Sri Lanka
Flying over Sri Lanka gives me chills, since some of the worst turbulence cases happened exactly in this region. Couple of times stewards had to be fastened and food delivery was postponed since nothing could stand on shaky surface!
Horizontal plane instability is fine, however when it goes into an air-gap and changes altitude - that's where funny part starts... Please, don't faint! It is 1/3 of what first couple of seconds after sky dive jump feels like.
These areas are based on my personal experience, and may not be the same for every traveler. Seasons may also affected weather conditions ¯_(ツ)_/¯