I'm flying up to Chicago tomorrow on American Airlines and coming back on Sunday. While up there, I'm getting a new MacBook Pro and iPod touch because I'm selling my old iBook to my sister. I've read online that the Dimensions of the MacBook Pro box is 17"x17"x3.25". First off, can I get a confirmation on that? Secondly, if that's true, my check-in bag is too small for the box to fit in. I already have a backpack that will be my carry-on. Would I be allowed to carry both the MacBook Pro box and my backpack onto the plane? I've looked on the TSA and American Airlines site and couldn't find a definite answer, so if somebody could answer this, I would greatly appreciate it. I just don't want to be screwed and have to leave the box with my sister until she comes home late August.