My argument is not about the justification to making or owning a 747. It's the justification for how is it realistically possible for ONE person to own enough wealth to buy a 747 EVEN when his own intrinsic abilities are not great enough to build a 747. This is orthogonal to society pooling together wealth and building a 747 AND orthogonal to the actuality of a wealthy person purchasing a 747.
At best a human can probably output the utility equivalent of 3 other human beings if that human has super strength or genius level intelligence. But the ability to make a 747 which takes thousands of man years to make? What sort fair exchange did the person engage in, in capitalist economy to generate that level of wealth WHEN at best his own output can only be 3x the average human? Obviously the exchange he made is fundamentally unfair.
The thing with communism is that it's unfair. You distribute resources equally, then actors who don't perform get an undeserved portion of wealth. Capitalism on the other hand is fair in the sense that the amount of effective effort you put in the more wealth you gain? Or is it? Then how come in capitalism you get entities that own enough wealth to buy a 747 when clearly the amount of work that person can output is obviously not even close to the amount of work used to create the 747 itself? That's the issue, and it's a small issue.
The bigger issue is that the person who has enough wealth to build a 747 has assets that will grow in compound. He will get richer and this will eat the world as what's currently happening in the actual world right now.