So maybe just take the L?...
"Winning the nod means the city of Chicago will negotiate exclusively with Boring for one year over details of the project, which aims to connect downtown Chicago with O'Hare, about 15 miles and a $40 taxi ride away. A final go-ahead requires approval from the city council.Elon Musk’s Boring Co. Wins Chicago Airport High-Speed Train Bid -- Bloomberg
In its request for proposals, the city set a goal of connecting downtown with the airport in 20 minutes or less, with service every 15 minutes for the majority of the day. It also requested that fares be below the current rates for taxis and ride-share trips.
Currently, Chicagoans can ride to the airport for $5 on a Chicago Transit Authority train, taking about 40 minutes."