I've just booked my first flight on Alaska Airlines so apologies if this is a newbie question.
I purchased a ticket on Alaska 779 on Friday 11th August from STL to SEA. The booking process offered a seat map which showed everything unavailable except for a few premium class seats, for an upgrade fee. I presumed this was because I was buying the cheapest, non-refundable fare that I couldn't select an economy seat. Now I'm wondering if it's because the flight is oversold. Should I be concerned?