[hardwired]

I copied, pasted (into a new folder) and compiled your last posted code and got these in the console:

Code:

C:\jexp\flightInterface>javac FlightInterface.java
FlightInterface.java:84: cannot find symbol
symbol  : class ActionEvent
location: class FlightInterface
    public void actionPerformed(ActionEvent e){
                                ^
FlightInterface.java:69: addActionListener(java.awt.event.ActionListener) in jav
ax.swing.AbstractButton cannot be applied to (FlightInterface)
        exitButton.addActionListener(this);
                  ^
FlightInterface.java:85: cannot find symbol
symbol  : variable exitButton
location: class FlightInterface
        if(e.getSource() == exitButton){
                            ^
3 errors

Make the following changes to compile and run okay:

Code:

// Add import statement.
import java.awt.event.*;

// Implement ActionListener so "this" can be an ActionListener
public class FlightInterface implements ActionListener {
    // Declare exitButton as a member variable.
    // This puts it in class scope where it can be
    // accessed inside the actionPerformed method.
    JButton exitButton;

        startButton.setFont(new Font("Serif", Font.PLAIN, 14));
        // Remove the type declaration from the instantiation so
        // that exitButton is not a local variable hiding the
        // member variable (of the same name) which would remain
        // uninstantiated and thus have a value of null, causing
        // NullPointerExceptions when you try to access it in
        // the actionPerformed method.
        exitButton = new JButton("Exit");

I did not get the compile errors you reported. The console errors give the line number of the trouble to help track it down. Maybe you omitted a semi-colon somewhere above the actionPerformed method.