By honoring them by giving a day where the whole world(or just the US) mourns for the loss of the civilians. We honor them in the sacrafice they made to tell the world that even in the most peaceful times, you still have to be on high alert. due to 9/11 the airport has become much more secure, and due to this 9/11 serves to show the mistakes made in the past and what not to do in the present and in the future.
