Awkward one as can see website says its approved for airline use, but generally airlines prefer use of stage 1 car seats so with a 5 point harness. I'm also UK so know full well the limitations. The only car seat widely available in the UK and definitely approved for airline use that i've come across is Britax's Eclipse http://www.britax.co.uk/car-seats/car-seats/eclipse which has a 5 point harness