For many travlers there's always a debate about how big is too big for my carry on bag. I think some fliers don't even know there are rules for carry on bags. To help simplify things we've assembled the carry on bag dimensions for most of the major U.S. airlines. If you're flying internationally I highly recommend you check with your airline. The information in this article is accurate as of the date of this article, but as always check with your airline in advance in the event the rules have changed. We've linked to all of these airlines on the right side of this page.