Aircraft spotting or plane spotting is the observation and logging registration numbers of aircraft: gliders, powered aircraft, balloons, airships, helicopters, and microlights.

When spotting aircraft observers notice the key attributes of an aircraft. They may notice a distinctive noise from its engine or the number of vapour trails it is leaving. They will assess the size of the aircraft and the number, type and position of its engines. Another clue is the position of wings relative to the fuselage and the degree to which they are swept rearwards. Are the wings above the fuselage, below it, or fixed at midpoint, perhaps it is a biplane or triplane. The position of the tailplane relative to the fin(s) and the shape of the fin are also clues to its type. If it is an antique or light aircraft it might have a tail wheel. Some aircraft types have a fixed undercarriage while others have retractable wheels.

Other features include the speed, cockpit placement, colour scheme or special equipment that changes the silhouette of the aircraft. Taken together these clues will enable the identification of an aircraft. If the observer is familiar with the airfield being used by the aircraft and its normal traffic patterns, he or she is more likely to leap quickly to a decision about the aircraft's identity - they may have seen the same type of aircraft from the same angle many times.