Disappearing craft/craft with capability of being invisible witnessedIt is the evening of December 25, 2016, and though I feel like I may have a great amount of difficulty explaining what I saw, I will do my best to do just that as I find I have been stirred to my core.The night sky is something I spend a lot of time staring up at. Stars, planets, our solar system, the universe, etc. has been of interest to me as long as I can remember. I also might mention that I live almost at the very top of a hill referred to locally as Eagle's Point, which provides a significantly unaltered view of the Lehigh Valley below me, as well as the many airplanes that come and go from its international airport (ABE). Quite often I find myself trying to distinguish between celestial bodies and man made aircraft - and what I saw this evening was neither of the two. If it was man made, then it's some kind of black technology or secret NASA project.As I stood in my driveway I looked up and saw something shimmering or flashing in the eastern sky low to the horizon. This is not what I wish to report. As I looked away to gain perspective by looking at stars, I noticed what I thought was at first a slower moving shooting star. But as I focused both of my eyes, the only way I can describe what I saw fly directly over my head and home was a low-flying craft that was either utilizing some sort of malfunctioning invisibility device or was just initializing this device as it flew overhead. It was completely silent and, though I feel I am struggling again to explain this correctly, it seemed like it was only visible from below. Do you know how it is when a large plane flies low overhead (like at an airport) and is so low that you struggle to make out the whole form until it is moving further away from you? It was like that, except as it moved further from me (at a quick pace), though I kept expecting that I'd be able to get a better view, it just seemed to vanish.It was the strangest thing. It wasn't like I could see an actual craft or anything. It was more like... a disambiguation(?) of the sky in what I can best describe as an aerodynamic form. Maybe like the shape of a triangle, but not a perfect one; a longer one.I'm honestly not sure. My instincts are telling me to question what I saw, but this is not something that I'm in any way unsure of seeing.Feel free to contact me. I feel like I will never find out for sure what I saw tonight, but I'm quite sure it won't leave my thoughts any time soon. I'm a college-educated guy, pretty well-rounded in my own opinion. I would say that I certainly believe in extraterrestrial life, but I wasn't looking for it tonight.