I think that the OP and spouse will each need to get both a frequent-flyer credit card (the Barclays AA is probably best for their situation) to take advantage of cheap redemption rates when they are available, and a card like the Capital One Venture X, US Bank Altitude Reserve, or the Chase Sapphire Preferred whose points can be used as cash for airline tickets when necessary. They are looking at 16 roundtrip tickets annually. Even two cards apiece are not likely to cover that, but could make a significant dent in their air-travel costs for at least one year.