ParticleSystem

private var litAmount = 1.00;

function Start () {

    var playerController : ThirdPersonController = GetComponent(ThirdPersonController);

    // The script ensures an AudioSource component is always attached.

    // First, we make sure the AudioSource component is initialized correctly:
    GetComponent.<AudioSource>().loop = false;
    GetComponent.<AudioSource>().Stop();


    // Init the particles to not emit and switch off the spotlights:
    var particles : Component[] = GetComponentsInChildren(ParticleEmitter);
    var childLight : Light = GetComponentInChildren(Light);

    for (var p : ParticleEmitter in particles)
    {
        p.emit = true;
    }
    childLight.enabled = false;

    // Once every frame  update particle emission and lights
    while (true)
    {
        var isFlying = playerController.IsJumping();

        // handle thruster sound effect
        if (isFlying)
        {
            if (!GetComponent.<AudioSource>().isPlaying)
            {
                GetComponent.<AudioSource>().Play();
            }
        }
        else
        {
            GetComponent.<AudioSource>().Stop();
        }


        for (var p : ParticleEmitter in particles)
        {
            p.emit = isFlying;
        }

        if(isFlying)
            litAmount = Mathf.Clamp01(litAmount + Time.deltaTime * 2);
        else
            litAmount = Mathf.Clamp01(litAmount - Time.deltaTime * 2);
        childLight.enabled = isFlying;
        childLight.intensity = litAmount;

        yield;
    }
}

@script RequireComponent(AudioSource)