Those who are really interested in this may want to check out Flight Explorer (http://www.flightexplorer.com). They offer a personal version of their aircraft situation display software, which allows you to view a customizable map showing every plane in the U.S. as well as most international flights coming to or from the U.S. that are over the Atlantic or Pacific. You can also add filters so that the program only displays planes that meet certain criteria. For instance, you could view only 777s travelling to or from JFK. It really is a neat program, but it isn't incredibly cheap (something like $10/month for 10 hours of use and $2-$3 for each additional hour).