When i click on Jbutton i want a Jcombobox to appear in the Jframe but im having trouble doing this. Can anyone give me any advice i would be grateful.

heres the problem, im trying to make it so when i click on the button time, i get a combobox appearing on the frame.
Code:
 
import java.awt.*;
import javax.swing.JFrame;
import javax.swing.*;
import javax.swing.border.*;
import java.awt.event.*;

public class TravelAgentSystemGUI{

    public static void main (String args[]) {
	JFrame myJFrame = new JFrame();
    myJFrame.setSize(600,400);		//500 wide, 300 tall
    myJFrame.setLocation(150,250);	//150 across, 250 down
    myJFrame.setTitle("TravelAgentSystem");
    myJFrame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
    myJFrame.setResizable(true);	//allows user to resize the frame
    myJFrame.setVisible(true);		
	
 myJFrame.setLayout(new BorderLayout());       
 JPanel testPanel = new JPanel();
 testPanel.setLayout(new GridLayout(2,0));
 JButton moneyButton, timeButton, hotelButton, exitButton;
 moneyButton = new JButton("Money");
 timeButton = new JButton("Time");
 hotelButton = new JButton("Hotel");
 exitButton = new JButton("Exit");
 testPanel.add(timeButton);
 testPanel.add(moneyButton);
 testPanel.add(hotelButton);
 testPanel.add(exitButton);
 testPanel.setBorder( new TitledBorder( new EtchedBorder(),"Main Menu"));
 testPanel.setBackground(Color.RED);
 myJFrame.add(testPanel, BorderLayout.WEST);



TimeGUI handler = new TimeGUI( );
timeButton.addActionListener(handler);

myJFrame.add(airports);

}



}
Code:
import java.awt.*;
import java.awt.event.*;

public class TimeGUI implements ActionListener {
	public void actionPerformed(ActionEvent event) {
JComboBox airports = new JComboBox();
airports.addItem("East Midlands");
airports.addItem("Birmingham");
airports.addItem("Heathrow");
airports.addItem("Albertus");

    }
}