The recent Amerika Bomber supplement for Luftwaffe 1946. The subject matter ought to be obvious from the title, and obviously primarily covers the hypothetical Luftwaffe long-range bomber offensive against the US eastern seaboard, although there are of course a few sideshows in there as well. It contains more aircraft stats, including a number of US experimental fighters that might have seen service had such a threat developed, and the usual wealth of scenarios that you'd expect.

Please note that this is a supplement not a complete rulebook - you will need either Luftwaffe 1946 or Kamikaze 46 for the core game rules.