MAKE sure you are dep from the right terminal, at the right airport.
This is most important for cities like Melbourne Aust and soon to be Sydney Aust.
AVV and MEL are far apart, and some JQd flights to SYD do dep from AVV and not MEL.
So far I have not made this mistake, as I don't fly JQ... but for those who do, triple check your dep city is right...
And don't expect the airline to hold the flight because you arr at the wrong airport for your flight.
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QFi/QFd e tix/BP do not show EDITED (alphabet code) class of travel, VAd does tho.
Have been travelling QFi/QFd for many, many, many years, and EK with a QFi flight number, and have not ever seen class of travel on these.
AirNZ and SQ also do not show class of travel.
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For a cheap to fly country like TH, maybe they already know that something for Aud$150/Usd$150, is a subclass of J.
But Buzzard, your BP does show Business tho, maybe you didn't notice it.
Just had a look see, for a usual price, for DAD to SGN, is $132.50 base fare pre taxes, so, yeap, they must have given you an "opup".