I think the B-17 was the prettiest bomber of the war. I also think the British Lancaster was probably the best including the B-29.
The Spitfire was the prettiest fighter tho the BF-109 and FW-190 were close. Also the P-40 had a good look to it. even the Zero looked nice.
The Brits did develop a tachimetric bombsight late in the war but the heavy lifting was always done by the Mighty Eighth. Simply superior equipment. Pretty, who the F knows or cares.