I researched this pillow and others for a long vacation to Italy. After researching I bought the BCOZZY pillow. It does what it says. It provides support for both sides of my head if I lean one way or another.
My husband just returned from a trip to China. He was on the plane 'going there' for over 14 hours. He told me that the BCOZZY Travel Pillow was great for sleep. I have enjoyed BCOZZY during 20 minute 'power naps', when I'm sitting in a chair rather than laying down to sleep.
I must have 2 dozen travel pillows and not one of them has ever held my head in a position so that I could sleep on a plane. But.... this pillow was great. I slept all the way from CA to HI, during the day.