Wheelchair invisible

Years ago my husband and I were discussing odd situations we've experienced like seeing folks laughing or smiling (in an comfortable way) when they observe someone being sick meaning vomiting. Why is that? My answer has always been we're all relieved its not us because we know how horrible a feeling that is, when you are that nauseous. Perhaps it is the same issue when people see someone in a wheelchair, are they that uncomfortable? Are they just relieved it isn't them? I am not sure on this one, but definitely noticed it when I was being wheeled through the airport last week. It wasn't that I was too sick to travel, just too sick to walk long distances and stand in long TSA lines. Did not have it in me. But as I was being wheeled down the concourse I definitely noticed people trying not to notice me. They wouldn't move as we approached as if we were invisible, me and the wheelchair, my son and his bag, and the person pushing me. Surprising really, for me as I am always so aware and try to be courteous to everyone, especially someone with disabilities. But it was a noticeable difference as people just stood still and seemed not to want to move, would look past me and over me, refusing to look at my face and look down at me. Is it a reverse road rage? Knowing that they can't say anything to someone in a weaker capacity but really wanting to? Instead, I was just wheelchair invisible, not a real person, but a lesser one, a weaker one who did not deserve recognition or acceptance. Sad.