The sky has no limit, at least for now.

According to the Air Transport Action Group (ATAG), there are on average over 100,000 flights per day worldwide, which can double during the peak season. However, this is just a fraction of what is expected in the future. Boeing and Airbus estimate that the global fleet will double in the next twenty years, reaching 48,575 aircraft in service by 2042, compared to 24,500 last year. This means that there will be nearly twice as many flights and planes in the sky in the next two decades.

Despite the increasing number of flights, there is still a long way to go before reaching the physical limit of air traffic. The sky is vast, and even with 45,000 planes and 400,000 daily flights, it would not be filled. Even with a million flights, the sky would still be far from saturated. The physical capacity for air traffic is much higher than the current volume.

The vertical and horizontal distances between aircraft in flight are regulated and allow for relatively close proximity. Two planes can fly within 300 meters vertically and less than 10 kilometers horizontally at the same altitude. Collisions between commercial aircraft are extremely rare, thanks to strict regulations and safety measures.

To maximize air traffic flow, precise tracking of aircraft and optimization of commonly used air corridors can be implemented. In congested areas such as London and New York, exceptions can be made to allow planes to fly closer together. There is also a trend towards reducing congestion at major hubs by opening up new direct routes and expanding airports.

The main limitation for air traffic is not the sky itself but the capacity of airports. Expansion projects and the construction of new airports, such as Istanbul Airport, provide additional capacity. While there should be careful planning to avoid excessive airport construction, there is still ample room for growth.

In conclusion, the maximum number of planes that could fill the sky remains uncertain, but there is still significant capacity for air traffic to increase in the foreseeable future.