[06/07/2019 @ 12:20 PM] Still available from last month.
American Airlines has round-trip flights from Dallas (DFW) to Chicago (ORD) for $97, NONSTOP. August to December. Departures on Tuesday, Wednesday, and Saturday.
Note: Carry-on bag is allowed for free on American Airlines. You can avoid paying for seat selection by accepting the randomly assigned seat at the gate.