After flying, I have frequent gas and BM with mucus for a couple of days.

[Flier93]

Hi,
I have a problem that shows up only when flying in an airplane. After a flight, for a couple of days I feel urge to have a bowel movement almost every half hour.
However, it's mostly just unusual amount of gas with some either clear or fecal-colored mucus. If there is a bowel movement, BM seems covered in mucus, and there is again unusual amount of gas at the same time. There is never any blood.
After a couple of days (three or four usually), my digestive system is back to normal. I never had any mucus in my BM when not flying, and I never have such frequent urge to BM when not flying. I don't have any other digestion problems.
I tried to prevent the problem by not eating or eating just before the flight, or not eating while flying, or not eating specific food but I haven't noticed any difference when doing any of these.
I would like to know what would be the best way to prevent these symptoms, either by a specific diet or any over-the-counter drugs.

[Flier93]

Well, I have my answer now, it's colon cancer.