Flight
Chicago has two main airports with O'hare being the larger one. It is about 17 miles or 30-45 mins from the city depending on traffic.
Flight
Midway is technically located on the outskirts of the city of Chicago. It is a smaller airport but if you are flying Southwest this is their only airport they fly out of in Chicago. It is also closer to the actual city being only about 25 minutes or 11 miles away. Both airports are definitely fine, it just depends on your preference of airlines.