Flight
This is the airport you want to fly into, it serves all major airlines.
Travel Note
If you want to avoid a car rental, King County has excellent public transit. Light rail from the airport to downtown and buses go to all the major surrounding neighborhoods. Google Maps gives directions with times and bus stops using the "Transit" option. Paying with your phone for fares is easiest, more info is in the link below.
Train
Link light rail travels between Northgate Station and Sea-Tac Airport, making 19 stops along the way, including downtown Seattle. Link trains run every 6, 10 or 15 minutes depending on the time of day. Service is available from 5 a.m. to 1 a.m. Monday through Saturday and from 6 a.m. to midnight on Sunday and holidays.
Rental Car
If you do need a rental car, Turo is like Air BnB for cars, usually more affordable and easier to get reservations than with major companies.
Hotel
Hotel
Hotel
Hotel
Hotel
Hotel