Unfortunately I believe you are spot on. Of course these corporations are going to come to the conclusion that you need a vaccine passport of some sort because the government will use all sorts of economic and regulatory "carrots and sticks" to make sure that companies come to the "right conclusion". Welcome to the new Fascist States of AmericaAirlines are corporations and can require just about anything they want. You'd of course be able to fly privately. Any "vaccine passport" will not be enforced by state, federal or local governments, its companies that want a liability shield in place to relax costly measures that are hampering their business. They are asking for this.
The best argument in this thread is the one where you get Covid and can't hunt, call me crazy but if there's an slight chance of my hard-won cardio being diminished in the short (or god forbid long) term, you can stab me in the eyeball with that needle, happily.