I was going to sleep late at night, passing near a window I saw a weird light in the horizon east. The light was really far and was too near to the ground and too bright for a star. So I waited almost 5 minutes watching at her to understand if it was moving or not. It was lower than the height of a mountain range in the horizon of which the height is 2100 meters. After that, I began to see the light clearly moving toward me, following the side of the mountain.
In a couple of minutes that strong light was near enough to see that was an airplane. It flew low and slow, I heard the swish of the air and just a really soft sound of engine. Not common. It had a blue light on the edge of a wing and a red on the other, whereas an airliner here has a green one and red one. Then another double whit light flashing in the middle, and the strong light I saw in the horizon was what in a common airliner is called "taxi light" that is a beam of light used to land. The fact is that it was not a commercial airliner. It was incredibly huge and of the shape of a bat, with the wings that are curved toward in front (the opposite of a normal plane). The wings were enormous compared to the central part of it. The picture of a bat with open wings, that was the contour. At the end of the wings and near the center of it there was a some kind of missiles shapes.
My feeling was that I was seeing some kind of secret military vechicle, because following the direction where he came there's the biggest italian military base for the aviation (publicly known, north of a city called Treviso) and the direction where he was going was the high part of the Garda lake, where there are a strong military presence. I thought that it had some kind of trouble; I even thought that it was crashing because was really low and had that "light of landing." It was lower than the height of the mountains in front of me, so less than 2100 meters, almost 1500 meters I presume. It was so low that the lights of the villages and roads below, together with his own lights, allowed me to see him clearly, his shapes, those kind of missiles, grey color. I supposed that his owner had tried to mask the plane with those light, because I do not see the reason why a secret aircraft must have lights like all the other airplane, even if a little bit different. But with those lights, if that plane had been high in the sky nobody would notice it mistaking it for a common one. Another thing I noticed is that there were no other planes in the sky while the aircraft was passing. The only airplanes that I saw were incredible far in the horizon and changed trajectory, this is never happened before. Only after, I saw planes return as usual. This made me think again to a military approach.
So, there was the biggest human flying vehicle I've seen in my life upon my head, really low flight, really low sound (the sound of air he was moving was stronger than the sound of his engine). Seemed strange, I feared it would have crashed on another mountain in his path or on the ground. Then came a UFO and everything found a sense.
I heard as an impact on the air, like sonic boom, and in the same time I saw a white flash that lighted the air in the direction of the sound. Like the flash of a thunder, but without a thunder, and the sound was far, not so strong. I saw a dark object, too high to see a real shape. Didn't seem big and in some way it was a compact object as a sphere, but I said was too far. That UFO was exactly in the path of the other aircraft, higher but really near. What made me mad is that the giant bat plane did not go away, but went suddenly toward the UFO, going upward. The UFO remained in the position for just few seconds and went away in up at the same point from which it came. Again a far sonic boom, a white flash. UFO remained for not more than four seconds in total, from the first flash to the second. It went away out of the corner of my eye because I was watching the reaction of the aircraft. So the military aircraft went down again as before, made a great curve that I didn't understand why. Here, that airplane was passing above my home. I went in a window to the other side of the home just in time to see the airplane disappear beyond the mountain horizon toward west. After few minutes I saw common airliners return.