Capital One provides generic miles which can be used for any travel expenses. You book your travel and then use the Capital One "miles" to pay for it at a rate of one cent per travel mile, whether it be air, hotel, rental car, or time share maintenance. You don't need to worry about available award miles from the airline.
I think Larry is somewhat mistaken. When using Capital One points to purchase airline tickets it is not based on a rate of 'one cent per travel mile" but rather one cent per dollar cost of the airline ticket. For example, if the fare for a r/t ticket to ABC is $180 then you need 18,000 points to purchase that particular ticket (regardless of how many miles the plane will fly).