tl;dr – The Korean low-cost carrier adds another US destination.
Air Premia, the eight-year-old Korean low-cost airline, recently announced its newest US destination, Washington DC.

The route will debut this April, and when it does, Washington, DC, will be the carrier’s second East Coast destination. Air Premia currently flies to four US cities – Honolulu, Los Angeles, San Francisco, and Newark.
The route will operate four times weekly – on Mondays, Wednesdays, Fridays and Sundays – on the following timetable:
ICN → IAD: 10:05 departure, 10:50 arrival
IAD → ICN: 13:20 departure, 17:45 (+1) arrival.
Outbound from ICN is scheduled for 13h 45m hours, while flights departing DC for Seoul can take over 15 hours due to needing to avoid Russian airspace.
Fares are already on sale, and I’m seeing prices as low as $583 one way.

Notably, Air Premia flies a two-cabin-configuration Boeing 787 that features economy and premium class. The ‘Wide Premium‘ is essentially premium economy with seats that have a bit more width but do not lie flat (they do recline).

This is an interesting route choice for Air Premia, though maybe not unsurprising, as Washington DC has the third-largest Korean-American community in the U.S.