I have been thinking of getting a Rimowa carry on which measures H56xW40xL20cm but JetStar only allows 56x36x23 so off by 4 cm on the width. I only have one return flight planned from SYD to AYQ with Jet Star (flying J with CX to Oz so no problem from Europe to SYD) and just want/need to know how anal they can be on the carry on size. What about weight? I think we have 7kg included and how are they on a few kg over? Can the weight be combined as were two pax sharing a carry on? Same with the size (i.e. One carry on a little bigger than one pax allowance)?