My new job requires weekly travel and so I wanted to choose an airline loyalty program which would suit me best.
I am based out of Seattle and have an Alaska airlines mileage plan for now. However I heard from my collegues that Alaska airlines is a regional airlines(?) as compared to American airlines or United and that they are the best.
I have no clue reg which plan would b ebest for a person based in Seattle. I usually have to travel to westcoast but then my job can take me anywhere within US.

And one thing I wud like to add is that I am travelling by Asiana airlines in near future and can avail 20k or so miles for United mileage if I chose so.

Any advice in this matter would be appreciated.

Thanks