https://www.heraldnet.com/news/paine...tier-airlines/
I would imagine AS is going to treat this the same way they did when G4 decided to move in at BLI (declaration of war).
TBH I am surprised it took this long for a ULCC to show up at PAE. Seems like the ideal setup, small regional airport, the strength is typically leisure markets, sub-daily frequencies are viable.