You are in a plane, and hit a bird as your flying, how can this impact produce a large impulse, despite the plane being much bigger

It effects the balance of the plane, and slows it. Also you are likely moving faster than the bird, and it would be almost as if you are hitting a brick. However when it makes the plane impulse then it means the sudden loss of speed (even if it is a small bird) that is keeping the plane in the air causes the planes engines to struggle for a short amount of time, while it tries to recover the little amount of speed it has lost (the engines HAVE to regain full speed or the plane will turn to the ground, maybe not ALL the way but it still will lower the nose.

Hope this helps,

Miri

54 degrees incident angle = reflected angle

angle is from normal turned to line of ray