How to make plane seatbelt smaller for slim child?

[Seatbeltconundrum]

Hi! Does anyone please have a solution for how to make an airplane seatbelt smaller for a slim child? My daughter slips out of the bottom easily (and frequently) and after the recent airplane door blowout in the US I am paranoid about this.

I have seen the CARES harness but it seems like not all airlines accept it and I'm not sure if would fully stop her slipping out of the bottom.

I have googled to the max but not found anything else to shorten the belt. Does anyone have any tips? I am wondering about bringing a travel pillow and sitting her within it? Thanks!

No advice but it might be useful to know how old your daughter is and her weight/height? I'm guessing she's too big to use a car seat?

My 2 year old has used an airtushi inflatable booster seat which you can thread the seat belt through

Would something like a trunki boostapak or bubblebum work?

I think the CARES harness is your best option. Have you called the airline you're flying with.
It's very unlikely you'll find anything to shorten the already installed belt as that would compromise its safety.