Just been on a massive mileage run and have enough in the bank for PFL, I actually went to Algeria for 4 hours on the same run. You don’t need a visa if staying at the airport for less than 24 hours. I flew LHR - CDG - AMS - BLL - AMS - CDG - ALG - CDG - AMS - BLL - AMS - CDG - LHR. All worked out well, tired from all the flights and slept on most of them.