Sentou Yousei Yukikaze

Pilots, wars, aliens, physical and psychological action. While NGE is a mecha anime, in Yukikaze a fighter-jet is being operated. Stories that are a bit more complex than it would initially seem. 

They are both animes dealing with airplanes. 

Both involve some kind of war between the human race and aliens. (In KnMYnB this story is more or less pushed off to the side ) Both are visually stunning pieces of anime that are a treat for the eyes.  

Both animes revolve around a military person and their relationship with a vehicle controlling A.I. and together they have to fight against an extraterrestrial threat.  

Both are about Flying Both have Air Combat Both are about the Main characters finding themselves Both are slowly drawn out Both have a lot of underlying subtexts that are never directly said. 

same style an extraterrestrial force invades the earth and Mc has to save mankind. both have good Dogfights (battles between planes) for those who like planes, it is more than recommended to watch 

Both have great aerial combat scenes. Yukikaze is more modern themed aircraft. While Toaru is more "unique" themed. Yukikaze isn't a romance anime unlike Toaru. 

Both are visually stunning pieces of anime that are a treat for the eyes, especially during action sequences. But more importantly, they both share the "human race at war with aliens" kind of story. 

Both of them are about war, dogfights and personal problems. The main difference lies in the fact that Yukikaze is SF and Simoun is more like Steampunk, but if you'll like one of them at least a bit, you'll most likely enjoy the other one. Both series also have a wonderfull Soundtracks, fitting the events in the air and on the ground. Simoun is also known as a yuri anime, but it's not really like most of the yuri series. 

If you liked the full CG animation air combat battles, you'd like both Macross Zero and Yukikaze 

One pilot has the fate of Earth in their hands when aliens attack to annihilate earth. The pilots also have similar social problems. 

Aliens are attacking Earth and trying to take over and destroy everything but humanity tries to find ways to fight back. Both anime are sci-fi, dark and have similar Anime styles. 

Mecha airplane pilot stories... Both have AI's though Macross's Sharon leans toward the dark side. >.< If you like this airforce, pilot, mecha type than I'm pretty sure you'll enjoy Macross Plus. 

Similar atmosphere and story elements; both fair better on ideas and visual experience rather than story and characters; heavy use of CG, though Yukikaze is far better