They had few left which is why the B-29s used in the firebombing raids stripped most of their armour and all their machine guns in order to carry more bombs. The Germans on the other hand had Me-262 jet fighters. Because of the short range of the early jets, the British Meteors could not have been available to escort our B-29s, while the Germans flying to protect their cities against an atomic attack could have engaged US bombers before they could reach their targets. Once airborne the Me-262 had about a 100 mph advantage over the P-51 Mustang. Considering that the Germans had tried to develop their own atomic bomb, I don't think they would have considered one or two B-29s flying towards one of their cities as non-threatening, especially since the B-29 had been exclusively used in the Pacific.