I can confirm that this was over Shilage (Mission 18), and that I was able to shoot him down along with the rest of his squadron in less than a minute.
I managed to hit Wit and Seymour before the script triggered, so technically, it still counts as a shootdown/shoo-away (my unofficial term for what happens in every other mission with Mr. X, ala he gets hit a few times and runs away to fight another day.)
I can't confirm how, because I've not been able to replicate it, but I can confirm I didn't use any cheats (engine or otherwise), hacks, mods or other subversive techniques.
Ok, the two second thing was a slight exaggeration. But it took me less than a minute, less than thirty seconds to do.
I know, Each time I faced him, he didn't even get a shot off. It took me about two seconds for me to cause him to retreat in both Two Pairs and Farbanti.
In Operation Beehive, it took me the same two seconds to shoot him down.
I repeat: Each time I faced Mihaly, he never got a shot off. It took me about two seconds to either trigger his scripted retreat or blow him out of the sky,
Rank S, Ace mode. Not bad for my first Ace Combat game.
Mr. X isn't a threat, he's a laughable joke.
I almost did so. In both Two Pairs and Farbanti, I came quite close to shooting down Mihaly. He didn't even get a shot off.
Now, in the final battle over his castle? I one-shot him. Took me about two seconds, and he didn't even land one shot.
I really hate to say this, but "Mr. X" is a joke.