This photograph of 212 aeroplanes flying over San Diego has a number of interesting points for the student of aerial
air traffic. First, it shows that two hundred aeroplanes will fill the sky of a city, and unless well directed by air traffic
confusion and lead to accidents: Second, the fact that the flight of all these aeroplanes was directed from the ground b
that radio-telephony can be used as a means of communication between officers in charge of enforcing traffic regulation
makes evident the necessity of adopting the system of "altitude levels" and "one-way" airways, proposed and adopted by
ica, the Aerial League of America, the Aerial Touring Association and other national aeronautic organizations.