I posted a new video showing how to fold a quilt. (If you get my newsletter, you may have see the video already.) The key is to always fold quilts on the bias.
When fabric is folded on the straight of grain, the fibers are more prone to be damaged which leads to permanent creases forming in your quilt. TIP: This is why bias binding wears better on the edges of your quilts!
I fold quilts to fit inside my Eagle Creek Pack-It Folders which go inside my suitcase when I travel. I buy them at the Container Store but you can probably find them elsewhere. They come in a variety of sizes so be sure to pick the one that fits your bag.
I like to use these for quilts and for clothes. They are breathable but water-repellent. They disguise the quilts in my bag which, I hope, make them less likely to be stolen. I put the full Pack-It folders inside huge Ziplock bags which serve 2 purposes: if my bags are rained on the bags keep things dry and the Ziplocks are another theft deterrent.
Eagle Creek has other packing products. My newest fav is this packing cube. It has an extra zipper that compresses what’s been packed inside. Great for clothes—or fabric!