r/TR3B

So I was in the back seat of a car, (my freind was driving) and I was literally thinking "Haha, wouldn't it be awesome if I saw a ufo" and I kid you not, I look out the window and I see one. It's really, really dark gray. It wasn't quite black. And it looked like a triangle, but here's the part where I think it isn't a tr3b: it had a rudder. And then, once I looked at it, it just went up into a cloud. Like straight up. And my friend saw it too, so im not insane. And the cloud is slow moving, but the "plane" hasn't emerged yet like a normal plane should. So what was this?