I've always noticed the face, but never the helicopter until now. That said, I never understood why they used a so-called character symbol because, as Urban pointed out, the Vietnamese language uses the Latin alphabet, unlike Chinese or Japanese. Maybe it's an ancient symbol of some sort.
Salve, Regina, Mater misericordiae
Vita, dulcedo, et spes nostra
Salve, Salve Regina
Ad te clamamus exsules filii Eva
Ad te suspiramus, gementes et flentes
O clemens O pia