I also want to point out that skipping flying isn't an option for everyone. I live in Texas, my family lives in Alaska, without flying it would take me approximately a week to get there, and involve somewhere around 3000-5000 miles of driving and a ferry trip. There are no trains or buses. People in Hawaii couldn't leave without air travel or a long and very expensive boat ride. Business travel from coast to coast would be crippled without air travel, and travel to other countries would be nearly impossible....
As for checking the colostomy bag...partially fill it with fecal matter and form the rest from C4. A friend's relative consistently used a bag to smuggle drugs on airflights, and was never caught.