Yup, all "radiation" is not the same.

It's kind of cute, the way eating radioactive isotopes is being compared to absorbing radiation energy from flying. Ah, the news outlets, they would never dumb-down any scientific information. /snark

The plane ride ends in a few hours. Ingested isotopes do not. You cannot walk away from the very molecules of your being.

Duration matters, and when you've absorbed the SOURCE, duration doesn't end until every single atom has done it's thing. You can't get away from it.

Kind of like saying: Look, I can wave my finger through this candle flame, and I don't get burnt! So you go right ahead and leave your finger in that candle for 8 days, you won't get hurt either!

(If you've never waved your finger through a candle flame, I suggest you try it. Doesn't hurt a bit. But the longer you leave it there....)

Here's a little fun with radiation. Remember, kids, duration is the key!
http://xkcd.com/radiation/