Yep, been mentioned before. The most interesting answer to this was sleeping gas and the flight crew changing everything that would keep time for you. Also add in the sheer stupidity of people to not understand how timezones work so they are confused when they land, enough to keep the conspiracy going.
Or, all of those flights are lies, that one was awesome too, since I was on one a few years back.
Or, jetstreams, perfectly boost your speed when traveling in the southern hemisphere, no matter which way you are going. Yep, multiple intelligent jetstreams.