If light-speed travel was possible, would the traveling object become invisible?

NO BECAUSE THE OBJECT WILOL BE MOVIN FAST ULL C IT ...BUT U JUSS WONT NO WEN U C IT...U NO WAT IM TALKIN BOUT.....

Perception and Observation of the viewer.
To the person traveling at or above Light Speed, all would be relative.
To the person looking at the sky as the other person passes, it would be an unseen event.
To the observer looking at the object as it approaches and as it passes further away, it would be a visible object.
The Blue/Red spectrum shift would be in action.

It would be invisible to a stationary external observer, regardless of whether  the object was approaching or receding from the observer.  If the object was receding, the red-shift would reduced the perceived light frequency to zero, and if approaching the blue shift will shift the light frequency to well above cosmic ray energies, also invisible.  In fact the object does not have to reach light speed to become invisible to the eye--it just has to go fast enough so that red shift or blue shift place its spectrum outside the range of human vision (which is pretty narrow).

Firstly, I disagree with Lawn Gnome.

In answer to your first question:

YES, theoretically the travelling object would appear invisible to all observers.

* The object would appear invisible to the observer watching the object as it approaches
    - the amount of blue shifting / doppler shifting of any light reflecting (or emitted) from the object toward the observer would be infinite -- the object is travelling at the same speed as the reflected light so all reflected wave-crests will be bunched together so that they are effectively coincident. An infinite doppler (blue) shift would result in an observed infinite reflected-light frequency

* The object would appear invisible to the observer watching the object as it recedes into the distance
  - any light originating from the observer toward the receding object would never catch up to the object (as it is travelling at the speed of light) -- as such, this light would never be reflected from the object
  - any light emitted from the receding object in the direction of the observer will be infinitely red-shifted. There is a number of reasons for this, including the fact that a clock travelling with the object would appear to have stopped.

* The object would appear invisible (more specifically, infinitely small in length) to the observer watching the object pass by nearby (i.e. where the observer is not in the flight-path of the object)
- A property of special-relativity theory called "Length Contraction" (or formally referred to as "Lorentz Contraction" ) predicts that the length of an object (in the direction of its motion) contracts by a proportion that is dependent on its speed. The length of the object appears to contract to zero when the object is travelling at the speed of light.

Irrespective of all the effects that I've mentioned above, the object would be causally-disconnected from the rest of the universe due to the effect of Time Dilation. This would effectively render the object invisible anyway.

its wrong that human eye can't see a particle  if u  can give light-speed to a particle then u can also have light-speed and then u can see the particle easily