I keep coming back to the ll bean town and field blazer

it's likely not perfect in fit and details but it gets close to this idea of a modeless [BLAZER], or in another sense a capital B Blazer (to speak in terms of tokens, types and forms). it's not navy because a navy blazer is so american, it's details aren't one way or another to speak too loudly to trends (it's not a 70s broad peak lapel or a 2005 skinny suit. I don't want to fall into the trap of mistaking trend as timeless, but it looks to me like a jacket you could probably find a dozen times in the last 70 years). it's something that will have a pretty similar message no matter where you are in the world (at least, in all airports across the world)
another airport jacket I have in my mind is something in the same color and fabric, but a little longer with a zip and button closure. it could have 1-4 quietly pleated pockets on the front, but importantly hand warmer pockets somewhere to rest your hands while u wait in line. the collar could be a lot of things: less military than a stand collar, less formal than a notch lapel. the yohji jacket
syeknom posted could be a good riff on the same theme. the only thing I've found like this is a NdG jacket but I could never find photos of it on the net.
I really enjoy dressing for the airport, or any kind of travel. it's an extension of the independence and freedom I enjoy when it travel alone- travel is usually a stressful or at least involved act for people, so the last thing on their mind is paying attention to other travelers. airports are also very multicultural or cultureless spaces, and people travel for a million different reasons. all of this means there's no one to pander to, and I can dress however I want to. the only requirement is a bunch of pockets which are enjoyable to use.