I just returned from an overseas trip, about an 11 hour flight one way and a little over 12 coming back and wanted a compact travel blanket, mostly for my six year old to use.
After researching a bunch I settled on the Cocoon CoolMax Blanket, which I thought was great.
Its compact, about the size of a can of Fosters when in its travel bag, yet its a big blanket, 55" x 70", my son and I were able to share it.
It is 100% polyester, but soft, it has the feel of an old t-shirt. While that sounds thin, it is sufficient to keep you warm on a flight.
I will definitely be taking it on future flights and will keep it in my car for my child to use during long drives.