Making child/parent movement smooth instead of choppy

I have been trying to get my character to be able to control something (specifically a ship) when he is inside of a box collider trigger. My script is working exactly as I want it to, but the entire ship is very shaky from the point of view of the player (it seems smooth in the editor). I make the player move by parenting the player to the ship while in the collider, and removing this relationship when the character leaves the trigger area. Ignore the weird angles/controls (my ship model is rotated funny). Does anyone know how to make it look smooth as opposed to jumpy?

Here's my script

 using UnityEngine;
 using System.Collections;
 
 public class ShipControls : MonoBehaviour {
     public float speed = 10f;
     public float rotationSpeed = 10f;
     public bool enter;
     // Use this for initialization
     void Start () {
     }
     
     // Update is called once per frame
     void Update () {
         if (enter == true) {
                         if (Input.GetKey (KeyCode.UpArrow))
                                 transform.Translate (Vector3.down * Time.deltaTime * speed);
                         if (Input.GetKey (KeyCode.DownArrow))
                                 transform.Translate (Vector3.up * Time.deltaTime * speed);
                         if (Input.GetKey (KeyCode.LeftArrow))
                                 transform.Rotate (0, 0, Time.deltaTime * rotationSpeed);
                         if (Input.GetKey (KeyCode.RightArrow))
                                 transform.Rotate (0, 0, -1 * Time.deltaTime * rotationSpeed);
                 }
     }
 
     void OnTriggerEnter(Collider other){
                 other.transform.parent = transform;
                 if (other.gameObject.tag == "Player") {
                         enter = true;
                 }
         }
     void OnTriggerExit(Collider other){
         other.transform.parent = null;
 
                 if (other.gameObject.tag == "Player")
                         enter = false;
         }
 
 }