Hi Gracifer!
No worries for the flying part! All Anna's advices are good. To be honest, when I fly, I am more worried about blood clots than I am about my bag and well, I just take time to shake my legs and walk around and everything is fine. I had to change my appliance once on a plane. I had invested too much faith in the fact my bag would survive another day... This is not to be advised, turbulence are somewhat annoying when you try to stick everything together but really, it is still possible.
I would suggest you to make sure you are wearing a new bag that has a filter. That way, the blowing effect is smoother cause yes, you can sometime see it blowing. Nothing to do with a risk of exploding everywhere though. If you aver carried a bag of chip on board, you notice how it can get blown, well... it goes the same, but way milder.
So yeah, just enjoy the flight, don't worry too much and have everything ready just in case =)