Are you a DL retiree? I assuming when you say you pull up the flights and see the AF that you are doing that in DL TravelNet. If you are a DL retiree, you can use the AF flights, but you must buy an ID96 at the airport. Also, AF only allows nonrevs to standby for economy only. I would hunt around the different routings and try to stick to DL across the pond and then use AF inside Europe. The fall is pretty easy to get to Europe even in Business class if you pick your flights well.