The Other Darrin: Stagleishov's voice in the European version of the game is different from the US version.
No Export for You: Inverted. The Japanese players won't enjoy the PC versions of Assault Horizon, leaving them only the home console versions. However, it's still import-friendly for them.
What Could Have Been: Story author Jim DeFelice reveals on his website that when he was tapped to write the story he was all fired up to do one in Strangereal, the main Ace Combat setting. The Aces team had a more realistic story in mind.
He also had much more material that he would have liked to fit in to the main campaign, including a mission where players control an F-35B, complete with vertical takeoff and landing sections. This particular mission didn't happen due to technical limitations.
Also, he wanted to be able to blow up his house.
Fan Nickname: Callsign of Duty, as some players (and reviewers) felt the game felt more like a Call of Duty game than an Ace Combat one at times.