Almost 40 airlines exist that serve Chicago. It's possible to fly in to Chicago from any corner of the world and especially Europe.

There are many airlines available that are serving Chicago from Europe. The best part is that you will find these flights quite regularly. Thus you will never face problems getting to Chicago from Europe at any time of the day.

One of the prominent airports to get to Chicago is the O'Hare airport. You can reach this airport through Europe and you will find a number of flights to Chicago through this airport. This is the best rated airport in North America.

There is absolutely no problem reaching O'Hare airport because this is the airport which is connected to the maximum number of cities in the world. European cities form a major chunk of these.

http://gochicago.about.com/od/chicagoairportsairlines/p/ohare_airport.htm

You may also choose Midway airport in case you are a bit more cautious about your budget.

http://gochicago.about.com/od/chicagoairportsairlines/p/midway_airport.htm

In order to find a list of the airlines serving Chicago, you can find information from here also.

http://gochicago.about.com/od/chicagoairportsairlines/p/midway_airport.htm