I'm new to all of this and trying to read up quickly as I'm planning a trip to London this summer for myself, husband, and our two children (ages 7 and 2). We live in Baltimore and strongly prefer to fly out of BWI - but there's only one nonstop flight to LHR (it's on AA). We could fly out of IAD if it would save enough money to outweigh the hassle of the drive plus the parking fees for a 2 week trip (we can get a ride to/from BWI but not IAD), but so far I haven't seen any significant price difference (I've been watching airfares for a few months). So I'm assuming that we'll be flying AA from BWI.

I would like to sign up now for a credit card for airline rewards; I realize we probably won't be able to use those miles for the July trip, but we could use them for future domestic travel. We charge ~$1500-2k/month and always pay off the balance each month. We don't travel for work so only fly 1-2 times a year, usually to LAX via Southwest or United. I can't think of the last time we've flown AA. Given all of this, do you think I should get the AA card or Chase Sapphire? Any input would be greatly appreciated.

Thank you!