My dd will be 9 at the end of June. She is 53" tall and 70 lbs. We will be traveling next week and driving a rental car at our destination. In the past we have taken the foldable travel booster to put in the overhead bin on the plane, but her seated height now makes her too tall for it. We have also used bubble bum boosters for travel. Both of them that we have seem to no longer hold any air. I assume that means we should no longer use them either? That leaves me with no booster to travel with for her to use. At home she is still harnessed in Britax Frontiers, but I am definitely not taking one of those on the plane at her current age. I don't think I should take a chance on her being able to safely fit in a rental van without a booster. Should I buy another bubble booster? I think the myfit doesn't get great reviews, right? What advice can you offer? Thank you!