https://phys.org/news/2018-06-musk-company-chicago-to-ohare.html

The Boring Company said it will fund the project in its entirety, and that it plans to collect ticket and advertising revenue. No information has been released about estimated construction costs or when construction might begin.

"Neither our mayor, nor Elon Musk, is a patient man, so we expect to start negotiations immediately and construction as soon as possible, and we'll be putting this project online in the near future," Deputy Mayor Robert Rivkin said Thursday.