They could set up an efficient secondary market if they wanted to, without NFTs.

They could, but NFTs are a cheaper, more secure way of transacting.

Aiports overbook because there are always passengers that do not show up and they want to make sure their planes are fully booked.

That doesn’t have to be how they work.

Those late/missing passengers arent going to sell their ticket to other passengers.

What? They would love to.