Chicago - O'Hare International Airport (ORD) Part One: By subway and sky train

From downtown Chicago to one of the busiest airport in the US using public transportation; lowest fare possible though it may be inconvenient for elderly, wheelchair, and people with luggage.

Parts:
* L train Blue Line from Monroe Street station (by the Loop)
* From Union Station to Clinton Street station
* ATS (Airport Transit System) Terminals 2, 3 (domestic), 5 (international arrivals), Rental Cars, Peoria Charter, and Coach USA bus
* Multiple scenarios and possibilities

Featured Rental Car companies
Avis, Enterprise Car, National Car, Thrifty, Alamo, Budget

Notes:
* You need a top-up Ventra card to ride any L train (subway or elevated). Get one from the vending machine; $5 for the card, then add any amounts for the trips (a $10 or more is recommended).
* The O'Hare sky train (ATS) ride is free
* Blue Line O'Hare station is at Terminal 2, take the ATS to go to elsewhere; Terminals 1, 3, 5, Rental Car, shuttle bus, and Metra train station
* Should you be going to UIUC (University of Illinois at Urbana-Champaign) from O'Hare (and back), taking the Peoria Charter shuttle bus is convenient and affordable