The core difference between volleyball and air volleyball lies in the characteristics of the equipment, the size of the venue, the design of the rules and the threshold of participation, with the former emphasizing more on competition and the latter focusing on popularity.

Specific difference analysis
Characteristics of equipment

Volleyball: PU and other hard materials, weight 260-280 grams, circumference 65-67 cm, stable bouncing, but the strength of the ball is more demanding.
Air volleyball: made of soft plastic, weight 120-125 grams, circumference 75-78 cm, light texture and not easy to cause sports injuries, suitable for all ages.

Venue and net height

Volleyball: standard court 18 x 9 meters, surrounded by at least 3 meters of barrier-free area; men's net height 2.43 meters, women's 2.24 meters.
Air volleyball: the court is reduced to 12 x 6 meters to flexibly adapt to indoor and outdoor space; men's net height is 2 meters, women's net height is 1.8 meters to reduce the difficulty of jumping.

Rules and System

Number of people and position: volleyball each team of 6 people (including the free man), a clear division of labor (main attacker, deputy attacker, second passer); air volleyball is usually a 5-player system, no free man, the rules are simplified.

Scoring and system: volleyball is played in three out of five sets (25 points in the first four sets), with 15 points in the deciding set; air volleyball is mostly played in two out of three sets (15 or 21 points in each set).
Technical Restrictions: Air volleyball prohibits jumping on the line, stepping into the line of dunking when dunking, and there is no restriction on the number of times a player can hit the ball after touching the net.

Sports Characteristics and Audience

Volleyball: competitive, high requirements for jumping, strength, tactical cooperation, representative events such as the Olympic Games volleyball program, the World Volleyball Championships.

Air volleyball: emphasizes on recreation and safety, suitable for middle-aged and old people and non-professional groups, often promoted as a national fitness program.
Summarize
If pursuing professional competition and high-intensity confrontation, traditional volleyball is the first choice; if aiming at leisure exercise or low-threshold participation, air volleyball has more advantages. Through the differentiated design of equipments and rules, both of them serve different sports scenarios and needs of people respectively.