The full title of Flight 714 to Sydney is a recent change, bringing it closer to the original French Vol 714 pour Sydney. The English language translation was originally published as just Flight 714 back in 1968; the same thing happened with the Dutch (Vlucht 714) and a number of other translations seem to have taken their cue from one or other of these editions. But in the last decade the destination has been added, maybe to increase the album's appeal in Australia, maybe to create greater conformity, maybe for some other reason.
But however long the title is, it's a misnomer. For the whole adventure is an interruption from Flight 714, with the characters having temporarily disembarked in Djakarta (now Jakarta) for a refuelling stop, only to transfer to another flight. Only at the end of the story do they once more board a commercial flight, also numbered Flight 714 and we never actually see them arrive in Sydney. In between they wind up on a deserted island and make some highly unusual discoveries.
But however long the title is, it's a misnomer. For the whole adventure is an interruption from Flight 714, with the characters having temporarily disembarked in Djakarta (now Jakarta) for a refuelling stop, only to transfer to another flight. Only at the end of the story do they once more board a commercial flight, also numbered Flight 714 and we never actually see them arrive in Sydney. In between they wind up on a deserted island and make some highly unusual discoveries.