I've about 10 spitfires in London and my army in north-west france gets hit by lots of air sweeps from german aircraft. I see my spitfires intercept but the troops still take damage. Also the enemy aircraft never seem to suffer problems as next turn they are at full strength. So how can I stop the aircraft? Taking the city that they are based in is obviously one way but very difficult. Can I not shoot them down with intercepts?