Just wanted to say that we bought a CARES restraint for a recent trip, and it was excellent. Like you seriously couldn't be bothered carting a car seat as well as all the other junk that you need to take, and the CARES restraint is a harness that fits on to the seat and the seat belt and creates a proper shoulder harness for a toddler (in their own seat). Cost was about $120, for us we were very happy with it, because 1) it kept her still and stopped her from escaping, 2) it's similar to a car seat restraint so it was a familiar feeling for her 3) it fits in a little bag and we could take it in her onflight luggage very easily. And if there was a problem it would have actually provided some protection for her which a normal aircraft seat belt would not have done for a 12kg toddler. The hosties were all very interested as it seemed none of them had seen one before but it is all CASA approved.