42 Squadron
- 42 Radar Squadron
- 42nd Air Refueling Squadron
- 42nd Attack Squadron
- 42nd Battalion (disambiguation)
- 42nd Brigade (disambiguation)
- 42nd Division (disambiguation)
- 42nd Electronic Combat Squadron
- 42nd Expeditionary Airlift Squadron
- 42nd Flying Training Squadron
- 42nd Group (disambiguation)
- 42nd Regiment (disambiguation)
- 42nd Tactical Missile Squadron
- Marine Aviation Logistics Squadron 42
- No. 42 Squadron (Finland)
- No. 42 Squadron RAAF
- No. 42 Squadron RAF
- No. 42 Squadron RNZAF
- VA-42 (U.S. Navy)