Age old question. I have tried everything I can think of included multiple searches on this site.

My example URL is mydomain.com/login.php?aircraft_id=3542

$aircraft_id = $_GET['aircraft_id'];
echo $aircraft_id;   //This works fine to verify the $_GET is working

... bunch of login code to verify user ... if password verified:

 session_start()
 $_SESSION['username'] = $username;
 header('Location: test.php?aircraft_id=' . $aircraft_id);

I can not get this variable to pass to the next page for the life of me.

I have tried

 header('Location: test.php?aircraft_id=' . $aircraft_id);

 header("Location: test.php?aircraft_id=$aircraft_id");

as well as other forms of single quote / double quotes.

The $_GET is working as I can echo the $aircraft_id on the login page but once I submit, the header will not capture the variable to pass on to the next page.

Here is the form code:

<form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post">
        <div class="form-group <?php echo (!empty($username_err)) ? 'has-error' : ''; ?>">
            <label>Username</label>
            <input type="text" name="username"class="form-control" value="<?php echo $username; ?>">
            <span class="help-block"><?php echo $username_err; ?></span>
        </div>    
        <div class="form-group <?php echo (!empty($password_err)) ? 'has-error' : ''; ?>">
            <label>Password</label>
            <input type="password" name="password" class="form-control">
            <span class="help-block"><?php echo $password_err; ?></span>
        </div>
        <div class="form-group">
            <input type="submit" class="btn btn-primary" value="Login">
        </div>
        <p>Don't have an account? <a href="register.php">Sign up now</a>.</p>
    </form>