1. Just how tricky the US of A design concept can be. maybe it is better to revert to Civ5 UU (Superfortress bomber: USA is the only known builder and operator of this kind of superheavy bombers. what should make this unit more unique is a basic better defense VS Fighter attacks than anyone else.)
Other UU to pic instead: Redlegs (Artillery replacement, attacks twice,
@Boris Gudenuf kun did say something about US Army Artillery Corps of the 20th Century and how awesome they are compares to anyone else counterparts)