Are there nonstop flights from Dayton (DAY) to Seattle (SEA)?

No. The fastest connection is via Chicago, about 4h 42m of total flying time.

What is the fastest connection from Dayton (DAY) to Seattle (SEA)?

via Chicago ≈ 4h 42m, via Denver ≈ 4h 59m, via Dallas-Fort Worth ≈ 5h 46m (estimated flying time, excluding layovers).

from 15,000 ANA miles (economy, one way, based on the published award charts).

James M. Cox Dayton International Airport (DAY) to Seattle–Tacoma International Airport (SEA)・3,142 km

No nonstop flights. The fastest connection is via Chicago (ORD), about 4h 42m of flying time (layover not included).

With milesANA 15,000 miles+ (via ORD)Economy, one way, estimate. Tap a connection for miles by cabin.

None.

10 one-stop options, sorted by estimated flying time. Tap one to see the airlines on each leg and booking links.

Times are estimated from distance. Check schedules, frequency and availability with the airline or a booking site.