It always strikes me when these stories mention the UFO’s speed and altitude, usually presented as confirmation that the object is beyond known technology.
You cannot determine the speed or altitude of an unknown object visually! Close and slow looks just like distant and fast. Unless you have some other way to determine one of those variables (being able to judge the distance because you know the size of the object, for example), any claim of a UFO’s performance is bound to be bogus.
AFAIK the rangefinder on the targeting system is pretty good, with that data and the data of the plane (direction, altitude, velocity, etc...) getting the speed of an object is pretty trivial.
If this is indeed a bird, then you can definitely trust the sensor's data. If it's a smoke plume, something ethereal, ball lighting or anything not quite solid, the rangefinder will give false values.
You cannot determine the speed or altitude of an unknown object visually! Close and slow looks just like distant and fast. Unless you have some other way to determine one of those variables (being able to judge the distance because you know the size of the object, for example), any claim of a UFO’s performance is bound to be bogus.