unity3D使物体可以在空中平稳飞行且可以改变方向，到达一定时间或者某定点迅速上升至一定高度的脚本

可以使用刚体组件和物理系统来实现物体在空中飞行，并且添加代码控制方向，时间和高度。这里有一些示例代码：

using UnityEngine;

public class FlyingObject : MonoBehaviour
{
    public float speed = 10f;
    public float maxSpeed = 50f;
    public float turnSpeed = 5f;
    public float upSpeed = 30f;
    public float maxHeight = 100f;
    public Transform target;

    private Rigidbody rb;

    void Start()
    {
        rb = GetComponent<Rigidbody>();
    }

    void FixedUpdate()
    {
        if (target != null)
        {
            Vector3 direction = (target.position - transform.position).normalized;
            Quaternion lookRotation = Quaternion.LookRotation(direction);
            rb.rotation = Quaternion.Slerp(rb.rotation, lookRotation, turnSpeed * Time.deltaTime);
        }

        float currentSpeed = rb.velocity.magnitude;
        if (currentSpeed < maxSpeed)
        {
            rb.AddForce(transform.forward * speed);
        }

        if (transform.position.y > maxHeight)
        {
            rb.AddForce(Vector3.down * upSpeed);
        }
    }

    void OnTriggerEnter(Collider other)
    {
        if (other.CompareTag("Waypoint"))
        {
            target = other.GetComponent<Waypoint>().nextWaypoint;
        }
    }
}

这个脚本可以让物体飞行，当物体到达触发器时较平稳地改变方向，而如果达到了最大高度，则会迅速上升，达到预设高度。