FlyingEnemies.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class FlyingEnemies : MonoBehaviour
{
    public float speed; //sets speed

    void Start()
    {
        GetComponent<Rigidbody2D>().velocity = transform.right * speed; //tells object to go a certain direction

        //actually this shouldn't be called flying enemies since the script is attached to non flying enemies.

    }
}