Although it's a debatable stretch, I believe I just found out who the protagonist of Ace Combat 2 is.
Former Belkan Air Force pilot Axel Reichart. The evidence I found in-game:
MiG-31 "Schwan" Ace Axel Reichert Schwan 35 Male Belkan MiG-31 Foxhound 05 Shot Down (05/12/95) The Belkan Air Force 12th Air Division's top ace, he forged an impressive war record in conflicts throughout the world. He was given the nickname The Swan for having never taken a hit. After the war, he retired from service, and now works for a small nation as a mercenary suppressing any coup d'etat movements.
"Works for a small nation as a mercenary suppressing any coup d'etat movements": AC2's player character is a mercenary pilot suppressing a major coup d'etat.