It would be really nice if I could save contact information for people I frequently fly with into some sort of address book. For example if I were to fly with my family I could choose my wife and two daughters and it would automatically populate their data when I go to book their flights. I also frequently book tickets for my mother and father and this feature would save me and other frequent flyers a ton of time.
I agree it would be a nice feature to add it would definitely help me with booking tickets for my family as well. Because this is a customer to customer forum I recommend you send your suggestion to southwest directly so they can document it and hopefully add it in the future.