It has been speculated that Erich Klinsmann is the former identity of Yellow 13, leader of the Erusian Yellow Squadron during the Second Usean Continental War, depicted in Ace Combat 04: Shattered Skies. The following arguments are cited to support this speculation:
- Klinsmann flies a Su-37 Terminator, a plane closely associated with the Yellow Squadron, and sports a paint scheme very similar (if not identical) to theirs. If Klinsmann is indeed Yellow 13, his custom paint scheme and future callsign may have been inspired by the legendary Belkan Gelb Squadron ("Gelb" means "Yellow" in German/Belkan), who also flew the SU-37.
- All that is known about Klinsmann's life after Operation Battle-Axe is that he survived and disappeared off the radar. Since many former Belkan aces emigrated to other countries after the Belkan War (cf. Lorenz Riedel), it is likely that Klinsmann left, too. It is thus entirely possible that he went to Erusea and joined its military in the nine years between the Belkan and the Second Usean Continental War.
- Klinsmann only appears on Ace difficulty and Knight Ace Style. The aces who appear instead of him on Ace difficulty in the Mercenary and Soldier paths are Ashley Bernitz and Michael Heimeroth, respectively, both of whom appeared earlier in Ace Combat 5: The Unsung War as leaders of the Grabacr and Ofnir Squadron, respectively, which played the same antagonistic roles as the Yellow Squadron in Ace Combat 04: Shattered Skies.
- Yellow 13 was famous for having never lost a wingman in combat until Yellow 4's death at Mobius One's hands. In real life, Erich Hartmann, a German WW2-era ace with the highest kill count in aviation history (352 confirmed with an unknown number of probables), also claimed to have never lost a wingman. Note the similarities between the names "Erich Klinsmann" and "Erich Hartmann".
- Yellow 13 is portrayed as honorable and gentlemanly pilot. Klinsmann only appears in the game if the player follows the Knight Ace Style, which is associated with exactly those qualities.
- Klinsmann's callsign is "Reiher", which means "Heron" in German. Both Yellow Squadron's actual name (Aquila) and his callsign are named after birds.