There are three main ways you can redeem Capital One Miles: 1) You can use them to book travel through Capital One travel at a rate of 1 cent per mile; 2) You can redeem them as a statement credit toward recent travel purchases at a rate of 1 cent per mile; or 3) You can transfer them to one of more than 15 Capital One travel partners.
When you transfer the Miles to an airline or hotel partner, you can sometimes get more than one cent per mile, if you do it strategically. "Strategically" means looking for redemption options on specific flights or hotel stays where the miles would be worth more than one cent.
So if you want to take a business class flight to London on British Airways, and you see that it would cost $4,000 or 300,000 Avios points, you could transfer 300,000 Capital One Miles to Avios at a 1:1 rate, then redeem those points for that flight, netting you a value of roughly 1.33 cents per Avios, or 1.33 cents per Capital One miles.
You can often get better value for business class, first class, and international flights, so don't expect to get 1.33 cents per mile on domestic flights around the holidays. But if you put in a little work and look for sweet spots, you can further the value of your hard-earned credit card rewards.