In general you’ll find that economy needs to be oversold, and if they have spare seats in the next class be it premium economy or business or first class then they start selecting people from Y to bump up to PE and PE to bump to business etc. It’s better for the flight to go out with more paying bums on seats than empty seats in the upper classes.

I do think a nice smile etc has a part to play in upgrades but it’s nothing you can give guideline fail safe guaranteed advice on. I have certainly heard of it.

I think majority of airlines will go down the list of their elite customers for upgrades.

Upgrades are really worth going for on long haul flights especially for the bed or I guess Trans Tasman if it’s a special occasion and you won’t be forking out for it again anytime soon.

You can actually buy miles in different programs and fly business class for cheap. I bought AA miles and it should cost me ~ $600 odd to fly Auckland to Perth in Business class on Qantas. Their 737’s don’t exactly conjure up images of luxury. But the reality is a cheap NZ ticket would be around $450 so you’re paying $150 extra for business.

Emirates has apparently gone to using fare paid eg flexi economy to upgrade rather than status. I ‘think’ you could use expert flyer to assess loads to see chances of flight being oversold and getting an upgrade. Qantas is really infrequent. Qatar will send out fixed fares for upgrades (less than the cost of actual business class). NZ you can bid to upgrade if you haven’t attained any status. You can use credit cards to upgrade with points if you use a card like AMEX or to just buy the flight outright with points. EY you can actually just bid to upgrade the certain sector. Most of the time I think buying a sale fare in J is easiest as you get the dates you want and pick the seat you want. If you know any friends that could gift an elite airpoint dollar upgrade that’s useful also.

If you could share the route and airline that might help, and I guess dates count also eg school holidays, xmas etc and whether you have any status to bump you up the list.