United has round-trip flights from Chicago (ORD) to Phoenix (PHX) for $137, NONSTOP. Flights August to December. Departures on Tuesday, Wednesday, and Saturday. Origin/Destination reversible.
Note: United “Basic Economy” fares do not include a free carry-on bag. Only a personal item (like a small laptop bag) is free. Seats are randomly assigned for free prior to boarding. If you have the United MileagePlus credit-card, use the “free checked bag” perk.
Note: The personal item size on United flights is smaller (9-in/10-in/17-in) than Frontier or Spirit (8-in/14-in/18-in).
Read More Nonstop Flights: Chicago to/from Phoenix $137 r/t – United