I want to write this post to share my experience recently moving from the west coast to east coast with my luxury collection. That's always a big concern for me about expanding my luxury collection. Maybe one day, when my collection is too large, I'll consider driving so I can move all my stuff safely. Currently my collection is less than 10 bags and some shoes, SLGs, scarves and belts.
Since neither of us wanted to drive this time, my husband and I flew across the country recently and my luxury items had to fit in our carry-on bags. I told him the carry-ons are only for my designer items.

We sold all of our furnitures and shipped the remaining stuff in boxes across the country. In the boxes, I put any luxury packaging boxes (e.g. Chanel, LV, etc).
In my carry-on, my SLGs and luxury belts were packaged in their boxes or in other smaller bags if I can fit them nicely. Then I stuffed the smaller bags in large bags or on their own depending on the jigsaw puzzle. I wrapped the bags in soft clothes or dust bag and filled any remaining space with soft padding. I made sure the carry-ons were not so stuffed that closing them would dent the bags. Luckily, I only have a few pairs of designer shoes (e.g. Manolos) and I can fit them in the carry-ons with their dust bags. I put the actual shoe boxes stuffed with clothes in my checked bags. Finally, I carried my Neverfull as my personal item aboard. I wanted to avoid putting any valuables in my checked luggages. In the end, we arrived at our final destination in one piece and my bags and accessories were all in good condition. My Speedy 25 was a little squished on one side but it went back to normal after a day.
Hopefully, people find this helpful. I'd love to hear other experiences and tips if you have them.