| 1/00 | Lighter-than-air aircraft |
| 1/02 | Lighter-than-air aircraft Non-rigid airships (B64B 1/58 takes precedence; balloons B64B 1/4) |
| 1/04 | Lighter-than-air aircraft Non-rigid airships (B64B 1/58 takes precedence; balloons B64B 1/4) the profile being maintained by ties or cords connecting opposite surfaces |
| 1/06 | Lighter-than-air aircraft Rigid airships; Semi-rigid airships (B64B 1/58 takes precedence) |
| 1/08 | Lighter-than-air aircraft Rigid airships; Semi-rigid airships (B64B 1/58 takes precedence) Framework construction |
| 1/10 | Lighter-than-air aircraft Rigid airships; Semi-rigid airships (B64B 1/58 takes precedence) Tail unit construction (B64B 1/12 takes precedence) |
| 1/12 | Lighter-than-air aircraft Rigid airships; Semi-rigid airships (B64B 1/58 takes precedence) Movable control surfaces |
| 1/14 | Lighter-than-air aircraft Rigid airships; Semi-rigid airships (B64B 1/58 takes precedence) Outer covering |
| 1/16 | Lighter-than-air aircraft Rigid airships; Semi-rigid airships (B64B 1/58 takes precedence) Outer covering rigid |
| 1/18 | Lighter-than-air aircraft Rigid airships; Semi-rigid airships (B64B 1/58 takes precedence) Outer covering Attachment to structure |
| 1/20 | Lighter-than-air aircraft Rigid airships; Semi-rigid airships (B64B 1/58 takes precedence) provided with wings or stabilising surfaces |
| 1/22 | Lighter-than-air aircraft Rigid airships; Semi-rigid airships (B64B 1/58 takes precedence) Arrangement of cabins or gondolas |
| 1/24 | Lighter-than-air aircraft Rigid airships; Semi-rigid airships (B64B 1/58 takes precedence) Arrangement of propulsion plant (B64B 1/34 takes precedence) |
| 1/26 | Lighter-than-air aircraft Rigid airships; Semi-rigid airships (B64B 1/58 takes precedence) Arrangement of propulsion plant (B64B 1/34 takes precedence) housed in ducts |
| 1/28 | Lighter-than-air aircraft Rigid airships; Semi-rigid airships (B64B 1/58 takes precedence) Arrangement of propulsion plant (B64B 1/34 takes precedence) housed in nacelles |
| 1/30 | Lighter-than-air aircraft Rigid airships; Semi-rigid airships (B64B 1/58 takes precedence) Arrangement of propulsion plant (B64B 1/34 takes precedence) Arrangement of propellers |
| 1/32 | Lighter-than-air aircraft Rigid airships; Semi-rigid airships (B64B 1/58 takes precedence) Arrangement of propulsion plant (B64B 1/34 takes precedence) Arrangement of propellers surrounding hull |
| 1/34 | Lighter-than-air aircraft Rigid airships; Semi-rigid airships (B64B 1/58 takes precedence) Arrangement of propulsion plant (B64B 1/34 takes precedence) Arrangement of propellers of lifting propellers |
| 1/36 | Lighter-than-air aircraft Rigid airships; Semi-rigid airships (B64B 1/58 takes precedence) Arrangement of jet reaction apparatus for propulsion or directional control |
| 1/38 | Lighter-than-air aircraft Rigid airships; Semi-rigid airships (B64B 1/58 takes precedence) Controlling position of centre of gravity |