Have only flown with a bad cold once - as pax on a commercial flight. No problem at all throughout the flight. No problem at all as we started descending, other than the usual need to clear the tubes out. Once we got down to, I'd guess (from looking out the window) 5000' my ears started to feel slightly uncomfortable, but manageable. On final, I found the pain getting worse and worse to the point that I was close to shouting at the pilot that he had to go back up, my ears were going to explode if we went any lower. Ears continued to be painful for the next four or five hours afer landing.
Just my personal experience, of course, but it seems to agree with the textbooks.
FFF
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