Dear girls =) I need advice, anyone uses neck pillows for children on …

Dear girls =) I need advice, anyone uses neck pillows for children on the road or during travel, what would you recommend, soft inflatable ones or those that clip onto a belt? My daughter often sleeps in the car, now I'm thinking about something to put under her head. Can you tell me which is better or simpler to just put a small pillow under her head?