Moving Applet Problem

When image scroll in applet then a blinking on image is continuously working.how to remove this blinking..

import java.applet.Applet;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;

public class PlaneAnimation extends Applet implements Runnable
{
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    Thread t1=new Thread(this);
    int maxx=0,maxy=0;
    Image plane;
    @Override
    public void init() 
    {
        setSize(750,600);
        setBackground(Color.BLACK);
        plane=getImage(getDocumentBase(),"AnimatedAirplane.gif");
        t1.start();
    }
    @Override
    public void run() 
    {
        try
        {
            for (int i = 0; i < 800; i++)
            {
                maxx++;
                maxy++;
                Thread.sleep(20);
                repaint();
            }
        }
        catch (InterruptedException e) 
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    @Override
    public void paint(Graphics g) 
    {
        g.drawImage(plane, maxx, maxy, null);
    }
}