If the main goal is storage, you'll need to put down some cash to get up to 1TB i.e. in case of the Air. Plus you'd always need to bring a charger as well.
I managed just fine with the 500GB WD for such a trip, I also carry quite a few cards with me as plan B. The WD isn't cheap if you're after the big volume HD but will be a lot cheaper than the Air. Then again, HD vs Macbook so apples and oranges really.
If the main goal is storage, you'll need to put down some cash to get up to 1TB i.e. in case of the Air. Plus you'd always need to bring a charger as well.
I managed just fine with the 500GB WD for such a trip, I also carry quite a few cards with me as plan B. The WD isn't cheap if you're after the big volume HD but will be a lot cheaper than the Air. Then again, HD vs Macbook so apples and oranges really.