I wish I knew about some of this stuff listed in the post as I had some bad ear pain returning from the UK back home to the US.

I had a bad cold that I got near the end of my vacation a few years ago. My right ear plugged up on a flight from Belfast to Manchester, then later on it happened again going from Manchester to Atlanta. The pain went away for a short time during the layover then on my flight back to Michigan, I managed to sleep nearly 1.5 hours of that flight, and I woke up right at the moment the pilot said he was making the descent to Bishop Airport. Both ears plugged up bad with pain, and I realized then I can see why some babies cry at take off or landing. The ear pain cleared about 12 hours later, and the cold took another week to go away.