Disclaimer: I used to work at Apple in their online services division, and I know first hand that (at least during that time) they cared a lot about privacy (often against short to medium term financial gains)
Despite the fact that I want the banks to be disrupted, I'd rather have a Stripe or Square or Coinbase etc do it, and have Apple focus on other things.
There is no room whatsoever to compare Apple IDs with being force-fed sales pitches for unrelated items while trapped in an aluminum tube at 30,000 feet.
If you wanted to tilt at this particular windmill, Microsoft account IDs would be a better horse to ride. They provide little or no value to most Windows users, but the company does everything it can to drag you into their ecosystem.
To be clear, I have no problem with the airline offering a credit card. Put an ad in the flight magazine, maybe hand out brochures with the ticket folder. But having the F/As treat the whole airplane like a cheap hotel conference room, as breck describes, where people have shuffled in to listen to timeshare sales pitches or Scientology lectures in exchange for some stale donuts? No, that's not OK.
Ignore your twitching knee when I say this, but it's one of the things I like about Apple: "here's some money. Might I have one of those fine devices you have on display?"[0]
"Certainly my good sir! Let me fetch one from the back...here you are. Apple Care? No? A fine choice, sir! Have a nice day!"
No cajoling about some card. If you don't want the extended warranty, it's a simple "no" and done. No popups on their internet properties asking to join their mailing list. I give money, they give me stuff. I'm sure there's some dark pattern I've missed, but for the most part the experience seems to be free of such jackassery.
[0] Admittedly, this part needs work lately at their retail stores.