Flights Seattle → Chicago — September 20, 2026

One way · Economy · 1 adult · price per person

The cheapest itinerary observed for Sunday, September 20, 2026 on the Seattle–Chicago route: 1 stop itinerary (2 flights) via Las Vegas Harry Reid (LAS), from Seattle-Tacoma (SEA) to Chicago O'Hare (ORD), first flight Frontier Airlines F94204, departs 9:45 PM, arrives 5:38 AM 2 days later, total travel time 29h 53m including layovers, flight time 6h 28m (layovers excluded), $174 per person. Fare as listed by Aviasales: carry-on bag not included (personal item only), checked bag not included, changes not allowed, non-refundable. Price found in an Aviasales search on September 10, 2026 and read by AirSource on September 10, 2026, 21:20 UTC: it is not guaranteed and is confirmed on Aviasales at booking time. The cheapest direct flight observed: Southwest Airlines WN2194, from Seattle-Tacoma (SEA) to Chicago Midway (MDW), departs 5:35 AM, arrives 11:30 AM, direct, 3h 55m, $220 per person. Fare as listed by Aviasales: carry-on bag not included (personal item only), checked bag not included, changes not allowed, non-refundable.