Your piece meal examples will not convince any flat earther.
Said flat-Earther probably doesn't believe that there are satellites that can and do monitor the winds, including the jets streams.
The current winds say little of those winds ahead. I worry you are being a bit silly about this. So these jets, you say, are optimizing around jet streams?
I said no such thing!
But even before the flight takes off the flight route is chosen with regard to the current winds.
That changes a lot of things don't you think?
give enough fucks for that.
So they find the clearest path through jet streams or using them - and yet we trust they can accurately predict their gas usage when we can't predict the weather?
The jet streams at 30,000 to 40,000 feet are far more predictable than surface winds but even surface winds are not quite as fickle as you make out except for thunderstorms and the like.
When it is said that "we can't predict the weather" it usually just means that we cannot predict exactly where it will rain but the general weather conditions are usually fairly predictable over a day or two.
And even the likelihood of thunderstorms might be known even is not exactly where.
It's hard to swallow. I want to believe, but come on. It would make life a lot easier to believe. The pilots I met don't give enough fucks for that.
And how many long-distance international pilots have you met?
You can believe what you like but flights like the QF27 non-stop from Sydney to Santiago are flown on 6 days a week.
But even now QANTAS uses the Boeing 747-438(ER) 4-engined plane because there are very few alternate airports to use in case of an engine failure.
Though they expect to change over to the Boeing 787-9 during this year.
The return flight QF28 non-stop from Santiago to Sydney commonly flies very far south, sometimes close the 70°S latitude line .
As to extra fuel there is this:
Flight Review: Qantas Business Class Sydney To Santiago
There is a delay taking off-something technical about a sealant or adhesive and as nobody wants things to fall off mid flight no-one seems particularly bothered. It takes about an hour to rectify the situation and then we are taxiing down the runway with the captain explaining that they have 2 tonnes of extra fuel that will allow them to fly at a higher mach so we won't lose much time.
The maximum fuel load of that plane is 227,572 litres or about 183 tonnes and a typical flight might burn about 195,000 litres or 157 tonnes.
New Zealand, however, currently has slightly different ETOPS rules and Air New Zealand does currently use the Boeing 777-219(ER) for the Aukland to/from Buenos Aries route.
If you are interested, this refers to a post by a QANTAS pilot about the Santiago to Sydney flight:
This whole thread about that flight is worth reading:
A Flight over the Antarctic Sea Ice From Chile to Australia (QF28).
It has a post about another flight, this one flown by TWcobra:
Abishua, I flew the QF28 flight from Santiago to Sydney a few days ago. I mean physically flew the aircraft, a 747.
We flew within sight of the Antarctic, down to 71.5 degrees south. We can go further south on that route but are limited to 71.5 south by lack of line of sight to the ATC communications satellites over the equator.
That in itself should tell you the world is not flat, however, can you understand that airlines are commercial entities, where containing fuel costs are paramount to maintaining profitability?
Santiago and Sydney are almost on the exact same latitude of 34'00 south. Sydney's Longitude is 151 deg East and Santiago is at 72 deg W. To fly between the two cities I must cover 137 lines, or degrees of longitude.. Correct?
The flat earth model has the distance between degrees of longitude becoming much larger as we approach Antarctica. This greatly increases the east-west distance the aircraft must fly to cover those 137 degrees of longitude. In this case the flat earth model makes it physically impossible to fly the distance on a full load of fuel.
Yet that is what we did. Because lines of longitude converge at the pole, the distance between them is shorter the closer you get to the pole. This is how great circle routes works and why airlines always fly an approximation of a GCR. They do get modified by winds and airspace restrictions.
[In the post above] are two representations of the route we followed [and videos and satellite photos of the route]
The first [map] does not depict the lines of longitude as they are or even as the Flat Earth model presents them. The do show the jets streams however.
The second is the actual route we flew, which was basically a straight line GCR modified for the winds on the day, and the 71.5S constraint. It depicts the lines of longitude converging at the pole, making this route the shortest way.
It may not be congruent with your beliefs, but that's the way we fly between these two cities, and we do it because any other way would cost too much fuel.
Sorry the "Flat Earth" does not exist. That's all there is to it.