Jetstar regularly cancel flights on the cairns tokyo run. I have had personal experience of this and have had friends experience this too. I know friends who will fly pixie though moresby now because it is more reliable!. I have been stuck in tokyo for three days because two flights were cancelled and jetstar have hidden in the fine print that they will offer no help in regard to accommodation, it cost me a fortune in hotel and food bills. I do not fly jetstar in to asia for this reason.