Bike box or bag?

You can be, and are incredibly and extraordinarily lucky.

Have you seen the way they handle it? I've caught a glimpse of my bike bag being thrown around like a rag dolls to the plane's hold.

Were the people who have had their bikes ruined using dropout spacers? That's the most important thing. No amount of bubble wrap in the world will stop your frame or fork from getting bent if they decide to throw a heavy suitcase on top of your bike or something.

I know my bike gets thrown around, doesn't bother me much as everything on it is heavy and made of solid metal...

I'm sure it goes without saying that not every bike can handle this treatment. Anything with cables/gears/nice paintjobs requires quite a bit more protection.