There is no universally accepted “first plane spotter” in the way there is for some other hobbies. Aircraft spotting probably began almost as soon as aircraft themselves appeared. However, it is likely that the earliest enthusiasts were seldom documented.
By definition we have “plane spotter” – someone who systematically watched, identified, and recorded aircraft. Then the earliest documented groups appeared during the First World War in Britain. Observation posts were established to detect enemy aircraft, creating what became the foundation of organised aircraft spotting.
One of the earliest identifiable organisations was the precursor to the Royal Observer Corps. Observation networks operated during WWI, and the Observer Corps was formally established in 1925. Volunteers were trained to recognise aircraft types and report their movements.
As for a specific individual:
- No source that I can find appears to identify a single “first recorded plane spotter.”
- The earliest documented aircraft observers were military or civilian volunteers in Britain between 1914 and 1918. These were located around southern and eastern England, where German airship and aircraft raids posed a threat.
- These observers were based at fixed observation posts around London, Kent, Essex, and other vulnerable areas.
If we consider aircraft spotting as a hobby rather than military observation. Then historians generally note that aviation enthusiasts have watched aircraft since the first flight. But planespotting as a recognised hobby did not emerge until much later, particularly after the Second World War.