// Update is called once per frame
    void Update()
    {
        enemySpeed             = uiapi.GetEnemySpeed();
        numberOfEnemiesInScene = enemies.Count;
        if (numberOfEnemiesInScene < maxNumberOfEnemies)
        {
            SpawnEnemy();
        }

        // change flight navigation order
        if (Input.GetKeyDown(KeyCode.J))
        {
            if (flightOrder)
            {
                flightOrder = false;
                uiapi.SetWaypoint("Random");
            }
            else
            {
                flightOrder = true;
                uiapi.SetWaypoint("Sequenced");
            }
        }
    }