I know this is an old thread, but I thought I would share my recent experience.
I was able to fit two B30's in my carry-on roller bag which I carried onto an airplane. I put some light blankets on the bottom of my luggage so the handbags would have a padded surface to rest on, and then I stacked my two Birkins in their dustbags into the suitcase. I used some bubble wrap to separate the handbags, as I did not want the touret to press into the leather of the other handbag and leave a dent.
After an eight hour travel day, we all arrived safe and sound!
I was able to fit two B30's in my carry-on roller bag which I carried onto an airplane. I put some light blankets on the bottom of my luggage so the handbags would have a padded surface to rest on, and then I stacked my two Birkins in their dustbags into the suitcase. I used some bubble wrap to separate the handbags, as I did not want the touret to press into the leather of the other handbag and leave a dent.
After an eight hour travel day, we all arrived safe and sound!