The annual Chicago airshow is far and away the best showcase for modern military aircraft in the American mid west. In fact, it's probably as good as anything you'll see on either the Pacific or Atlantic coast, as well. Overseas airshow enthusiasts should seriously consider this show as an alternative to some of the better known events such as the Oshkosh AirVenture, which is a hugely hit-or-miss situation, unless you're a dyed-in-the-wool devotee of homebuilt and light civil aircraft. If you're after historic military aircraft then Chicago definitely isn't for you, but in this case you might be better served by some of the alternatives to Oshkosh, such as the Dayton airshow, held in the same area as the spectacular United States Air Force museum, or even the Willow Run airshow, which gets better with each passing year.
If you do come to the Chicago airshow then not only will you experience a great airshow, but you'll also have an opportunity to experience one of America's great cities. Set beside Lake Michigan, many miles of the lakefront are accessible by means of the parks which follow the shoreline. Near downtown, you can experience the world-class museums and art galleries clustered around Grant Park, take a river tour of the architecture for which Chicago is renowned, and go to the top of the Sears Tower, tallest building in North America.
The airshow is certainly spectacular, and the setting makes it unique in America. Where else can you see giant B-1 bombers passing in front of downtown buildings? And if you manage to find a spot on the roof of one of the buildings near the lake, then you can take photographs looking down on military jets, with the lake and pleasure craft below them. Since most viewpoints face east towards the lake, lighting for photography can be difficult for much of the day, a situation which isn't made easier by the infamous humidity and haze, but there are still plenty of places from which you can get interesting shots. The surrounding buildings, as well as parts of the lakefront which jut out into the lake, mean that there are plenty of opportunities for out of the ordinary photography.
Chicago is an especially good place to see some of the "heavy metal" of the American aerial arsenal, planes such as the KC-135 aerial tanker, B-1 bomber, C-5 Galaxy cargo plane, and occasional visits by the B-2 Stealth bomber or B-52 Stratofortress. As well, you're guaranteed that one of the American military jet teams, either the Air Force Thunderbirds or the Navy Blue Angels will be present - something you certainly won't see at Oshkosh. In addition, there are always flypasts by helicopters such as the Coast Guard Dolphins and the Army Apaches, and fighters such as F-14 Tomcats, F-15 Eagles and F-16 Fighting Falcons. The Chicago 2003 Airshow highlights page will give you a very good idea of what you can expect to be on display, regardless of which year you attend.