I bring my 3 inch queen bed sized memory foam mattress topper with me when I travel. It's fairly easy to roll up since it will squish.

My husband rolls it up like a sleeping bag, and then I sit on it to squish it as he stuffs it into a nylon laundry bag (the kind of laundry bags that college students usually use to bring laundry home to mom).

It easily fits into the car, and I would imagine that a twin size memory foam topper would be able to be rolled/squished enough to be able to fit into a backpack sized bag for air travel. If we ever travel by air, I would buy a twin size topper to roll and squish and pack in my luggage to bring it with me.

I also have a leg wedge pillow, a back wedge pillow, and a variety of bed pillows and throw pillows that I squish and bring so I can make the hotel (or relatives house) more confortable to sleep in.

At home, I sleep in a position that is similar to a recliner by using all my pillows and my leg-wedge pillow, and I can accomplish the same sleeping position when traveling by bringing my pillows with me. Hubby laughs at me because when we travel the trunk of the car is luggage, and the backseat is full of pillows in laundry bags and a queen sized memory foam mattress topper stuffed into a laundry bag.... but packing all my pillows and bedding and being able to sleep comfortably while away from home is essential!

Without all that stuff, I would never enjoy a trip because I would flare badly in pain from sleeping badly - so packing the backseat full of pillows and the memory foam topper is worth it for us.