werewolf,
Inside or outside of the plane, the final velocity of the ball would be 660 mph (not accounting for the wind, but if we account for that, you'd have been blown off the plane before the ball could come back for you

).
Newton's laws of motion dictate that velocities are simply additive, for an object 'a' being thrown from moving object 'b', the total velocity of object a is (a +

.
Einstein elaborated on Newton's laws of motion by adding the relativistic effects, making the equation for calculating motion:
(a +

* (c^2 / c^2 + ab)
Where a and b are small relative to c, the correction (c^2/c^2+ab) is very close to 1 and the sum of the motions are as described by Newton.
Where the values of a and / or b are a significant fraction of c, the correction factor becomes less than 1 and the total velocity is the sum of a and b times the correction factor, with the result that the total velocity is *always* less than c.
Since your hypothetical spaceship cannot actually reach the speed of light, let's say that it is travelling at a constant velocity of 99.9999% of the speed of light. When you shine your flashlight, the control panel will be illuminated in exactly the same manner as it would be if you shone the light on your keyboard at home right now. And if you measured the speed of light from your flashlight, you would measure its velocity as 'c'.
While the relativistic and quantum physical laws hold for the behaviour of photons *at* the speed of light, there's no meaningful way to determine what an observer such as you or I would observe if we were travelling at the speed of light, since that cannot occur. Given the zero time and distance solutions for a velocity at the speed of light, if we could reach that condition, it might be that we would 'see' everything in the universe at once (not sure if that would be a desirable outcome

).
You'll notice that I've limited my discussion to objects with a constant velocity (not accelerating). The special theory of relativity only considers objects that are not accelerating. To handle objects with acceleration (including responses within a gravitational field), one must invoke the general theory of relativity. By and large, the results will come out the same, although an object under acceleration *does* have a frame of reference of sorts, because of the acceleration.
BTW, the bulb wouldn't burn out either