If you need to rent a car when you are in Chicago I would
highly recommend going online to Discount Airport Car Rental. You do not have to pick up at the Airport but you can. They have several
places to pick up and drop off in the Chicago and surrounding area.
The cars are always new and deeply discounted so you will never pay brand name prices. If you want to pick up at O??Hare just go on line and put that in as your pick up spot and the car of your choice will be waiting. I have found that there is no better way to get a discount car rental in Chicago.