How can I include more than one class in a page.aspx

I can access to a class called Flight.cs writing this

<%@ Page Language="C" src="Fligth.cs" mce_src="Fligth.cs" %>

This works but i don´t know if it is the best way.

But I want to include a class called company that is in the file company.cs
How can I do it?

Thank your

It's better you can extract common methods/event handlers out of the company class, making them into a shared class that support all pages, and reference the new class methods in your flight codebehind.

You should just be able to put company.cs into your App_Code folder.