Originally Posted by pinniped

My thoughts:

(1) I believe the ANA recommendation was spawned by your mention of Amex Membership Rewards points. The idea is to move Amex point to ANA miles and then redeem seats on United using those miles. Do you have 80k or more Amex MR points right now? If not, this may be a more difficult path to take. (I don't see a lot of traffic here about an ANA mileage card via a U.S. credit card issuer.)

(2) ANA, if you do go that route, requires a R/T redemption. (There's a little open-jaw hack that some people use in a pinch, but you wouldn't need to do that since United has seats available both ways.) You'd book as many seats as you can with the ANA miles you have, full R/T itineraries, on United or US Airways metal. Then you'd book the remaining seat(s) on the same aircraft using United miles from your credit card signups.

(3) Fees on UA or US metal, using ANA miles, should be minimal. It's a good deal if you can do it.

(4) I probably would not wait until December. Late spring is a pretty good time to go to Spain...I can see these awards getting booked up. I mean, UA is relatively good about availability, but you just never know. Since you know dates and destination and the fact that you *do* want to take this trip, I'd book as soon as possible. Therefore, if you are *not* currently sitting on a nice stash of Amex Membership Rewards points, I'd quickly sign up for three AA cards and go four seats one-way on AA and four seats the other on United.