The more expensive travel pillows have Velcro or another way to fasten the pillow around the neck for support. This travel pillow was only a few dollars, but it didn't have a support strap. I created one with a button and hair tie. I also modified the rear neck portion of the pillow for more comfort.
Step 1: Button
Sew a button to one side of the travel pillow.
Step 2: Hair Tie
Sew a loop into the hair tie that fits snugly over the button.
Step 3: Loop
Sew the hair tie to the pillow opposite the button.
Step 4: Neck
The rear neck portion of the pillow seems too large and pushes the head away from the seat in an uncomfortable way. Remove the foam and tape it so it fits behind the neck more comfortably. Reinsert into the fabric cover.