St. Louis keeps quietly rebuilding its transatlantic connections. Icelandair has announced a seasonal nonstop between Keflavik (KEF) and St. Louis Lambert International (STL), starting 14 May 2027 and running through 24 October. Flights operate four times weekly — Mondays, Wednesdays, Fridays and Saturdays — on a Boeing 737 MAX 8 with 16 Saga Premium seats and 144 in economy.

It becomes Icelandair's 16th US destination, and the third transatlantic route from St. Louis. British Airways already flies the city to London Heathrow and Lufthansa has served Frankfurt since 2022 — impressive for an airport that stopped being a major hub back in 2009.

The interesting part is what happens on the ground. Icelandair and Southwest Airlines signed an interline deal in 2025, letting the two sell each other's flights on a single ticket with bags checked through. St. Louis joins Baltimore, Denver, Nashville, Orlando, Pittsburgh and Raleigh-Durham under that arrangement. Practically, that means a traveller in smaller Midwest cities can book one Southwest itinerary that ends in Iceland or beyond in Europe — and Icelandair gets a stream of connecting passengers to fill those 160 seats.

For Icelandair, the economics work because of geography and equipment. Iceland sits close enough to both continents that narrowbody jets like the 737 MAX 8 can span the Atlantic, keeping costs low. The airline, which built its reputation on Boeing 757s, is retiring most of them in favour of 17 MAX 8s, MAX 9s, and incoming A321LR and A321XLR orders. Smaller aircraft mean routes like St. Louis are viable where a widebody wouldn't be.

For Southwest, the partnership is part of a bigger pivot. The airline is chasing the loyalty playbook of Delta and United — extra legroom seating, planned lounges, a premium credit card, and now its first foreign airline partnerships in years. Until recently, a Southwest loyalist flying to Europe had to defect to another carrier; now Icelandair can carry them across on one ticket. There's even speculation Southwest might one day fly its own 737 MAX 8s to Keflavik, though nothing has been announced.

Why should a traveller care? St. Louis residents get a cheap, one-stop gateway to Iceland plus Icelandair's European network — including Madrid, which the airline resumes in April 2027 — without backtracking through a coastal hub. And with Icelandair serving more US cities than KLM, Turkish or Virgin Atlantic, all without belonging to any major alliance, smaller cities are clearly where it sees opportunity. Book early for summer 2027; seasonal Icelandair routes tend to be priced aggressively at launch.

Story via Simple Flying.