There is a simple macro view I don't see mentioned much: For the economics, in a word, the robots are
deflationary. Usually in deflation people lose jobs.
Then there is the old remark IIRC "deflation is the easiest problem in the world to solve -- just print money."
It may be that the current pair of low interest rates and low inflation are just from such money printing for just such deflation.
Then with the low interest rates, businesses can afford to borrow to do the R&D for the (more) robots.
Also generally with the money printing, there is more money sloshing around which tends to result in more hiring, more jobs, and lower unemployment, and sometimes even training new workers.
So we've got five together: (i) More automation (robots, computing, the Internet), (ii) low interest rates, (iii) low inflation rates, (iv) high stock market, and (v) low unemployment rates. With tariffs and trade deals, we may have more jobs for low skilled workers.
I'd like to know in more clear terms just what Amazon is using cargo planes for: The usual idea is to use boats and trucks to move products to a retailer's warehouse and then use something like FedEx, UPS, or USPS from the warehouse to the end of the last mile.
A guess: Amazon wants a warehouse in each major city, maybe 100 - 200 in the US. From each such warehouse, they deliver to the end of the last mile by small trucks. For the popular items, they stock these warehouses via trucks. Then they also have a huge central warehouse, stocked by truck, that has all the rare items and each day have their planes fly at night moving the rare stuff that has just been ordered to the city warehouses for delivery by truck during daylight. Maybe.
Amazon needed a lot of computing for their Web site so setup their server farm(s) and also provided such computing to anyone via AWS. Well, Amazon needs lots of warehousing and small truck delivery so maybe wants to provide that to every other business that needs warehousing and small truck delivery.
In some cases there're big efficiencies there: E.g., for a lot of items, it comes out of the factory for, say, 10 cents but the consumer pays maybe $2. The $1.90 goes for advertising, order taking, warehousing, shipping, payment, and some earnings. Well, Amazon can save a big chunk of the $1.90 which for the US, and much of the world, would be one heck of a big increase in economic productivity and a lot of deflation needing still more money printing! My guesses!
For more, why do people need private cars? Sure: A big reason is for shopping, e.g., getting groceries. Well, do warehousing and small truck delivery well enough and can replace a lot of the need for private cars, even for refrigerated grocery items, milk, butter, cream, eggs, lettuce, ready to bake pizza, and maybe even ice cream!