While obviously the line in Mission 3 "A safe return completes the mission" is meant to tell the player that they need to cross the return line to finish the mission once they've destroyed all the targets, there's another meaning to it: even from the start of the game ISAF is already strapped for planes and personnel and cannot afford to lose any more. Just completing the mission objectives means jack squat if the organization folds from the material losses. Sky Eye knows that the mission is a huge gamble, and he's calmly begging all the pilots to return home safely. It's also a subtle clue that later missions (like Mission 5, Lifeline) may not auto-complete once the last target is destroyed, and that something is going to force you to make a run for it.
With a bit of fridge heartwarming: A commenter on this video had theorized that Yellow 13, after shooting his enemy down and seeing the plane spiral into the narrator's house, had actually searched the remains of the house to pay respects to the accidental casualties, and while he was there, found some music sheets. And on one of them was the same song that the narrator and his father used to play; The very same song that Yellow 13 plays alongside the narrator in the bar.
The giant missile inside Megalith looks exactly like the V2 in Ace Combat Zero, which has the ability to wipe out half the cities in either Osea and Yuktobania, both of which are half the size of the Usean Continent. That's right, one V2 will render Usea uninhabitable.
had theorized that Yellow 13, after shooting his enemy down and seeing the plane spiral into the narrator's house, had actually searched the remains of the house to pay respects to the accidental casualties, and while he was there, found some music sheets. And on one of them was the same song that the narrator and his father used to play; The very same song that Yellow 13 plays alongside the narrator in the bar.