AERO-ALPHABET - Ok

Okamura (Okamura Seiskujo Kabushiki Kaisha - Okamura Manufacturing Company Limited) {ErZ}
Okamura N-52

Okay (Okay Airplane Co. (C. N. Martin) - Okay . OK . USA)
Okay SK-1

OKB-1
OKB-1 140
OKB-1 150
OKB-1 EF 131
OKB-1 EF 132