I'd recommend strongly using Composer (http://getcomposer.org) to manage your application's dependencies. Use the autoloader that Composer provides to autoload your classes and you won't have to manage them yourself, thereby avoiding the issue entirely.
In order to have access to those classes in your application, pass Laravel's container to your routes with the use keyword:
$app->get('/', function () use ($app, $container) {});
You're now able to access anything in the $app instance and anything from the $container in your route.