We gate checked ours 3 times and it survived. I think the problem of the stroller going on the plane is the banging around it will get and the bag will not help with that. Ours suffered a bang but I didn´t notice it dirtier. Securing the canopy is important because it is a good grab spot for someone who is not familiar with how easily it will pop off.
Sorry, can´t help with the bag part. It is a great stroller for Disney. I will miss it this year.