Muv-Luv Alternative: Total Eclipse

In the year 2001, the Japanese Empire’s attempt to develop a next-generation Tactical Surface Fighter for their army had hit a dead end. To solve this problem, they decided to work with the American government to build upon their 3rd Generation TSF, the Shiranui.
The project was given the code name XFJ, and Takamura Yui, a 1st Lieutenant in the Royal Guard, was put in charge of it.

Yui had always been against any attempts to work with other countries to develop a new TSF, and she departed for Alaska’s Yukon base with a heart laden with worry and dissatisfaction.

2nd Lieutenant Yuuya Bridges, an American, was also headed to Yukon Base as well. He'd been chosen as the main test pilot of the XFJ Project, and hated Japan because of the sad circumstances of his birth. He too, was very unhappy with the project.

Of course, the two quickly collided, and completion of the project seemed impossible. But if it failed, Japan was doomed...

Set on an Earth pushed to the brink of destruction, Total Eclipse is an intense human drama about the race to develop a new TSF!

[From Official website]