Skymiles, United Explorer, Alaska miles members? question

[Selino631]

I feel dumb for not doing this years ago cause i'd have a big chunk of miles by now. but i'm trying to decide which Airline i should get a miles credit card through. Any advice?

I like Delta, they have decent planes and cheaper. Plus some nice flight attendants, and they are easy to fly with firearms

The reason i'm thinking United is because they have a major hub at IAD, So its easier for me to find flights from Alaska to there.

And i mentioned Alaska Airlines because i believe since they are a Skyteam member. that i can use their card for Delta flights?

https://www.theexplorercard.com/MPYoureIn30kAFW.aspx

http://www.delta.com/content/www/en_US/skymiles/earn-miles/earn-miles-with-partners/credit-card-partners/earn-30000-bonus-miles.html?psboth=CCSG_Google_PA_Delta%20Card%20Offer_Broad

https://www.bankofamerica.com/credit-cards/products/alaska-airlines-credit-card.go


^ from what i understand from this. If i get the Alaska Card. i get FREE 25,000 miles instantly? where as with the other 2 cards i have to spend money beforehand?

this is my first Credit Card so im not sure how all this works. thanks