The key to this paper is the “grand challenge” of creating a network to serve the diverse needs of simulation of air transportation.

Following the introduction, there is an enumeration, mostly by narrative, of economic parameters in Section 2, capacity parameters in Section 3, and the vertically focused interests of simulation of air transportation in Section 4. Section 5 is a discussion of the extensive databases needed; this enumeration is excessive. The enormous magnitude of air transportation is evident to scientists and engineers, who might even have become aware of it from cursory mingling with the multitudes in a typical airport.

The paper then makes two important points. Firstly, simulation of air transportation, though enormously complex and extensive, pays off handsomely in large economic operations, and with safety improvements and growth. Secondly, the assemblage of methods, computing, and data to investigate diverse aspects of operations and facilities of air transportation requires global partnerships with numerous contributors and users, each pursuing their own interests. Their cooperation enables individual simulation projects to attain the appropriate depth and thoroughness. This is where the “grand challenge” really applies. The concept of such a network is discussed in Section 5, and is followed by examples of its usage in Section 6.

Wieland and Pritchett omit references to the many very successful similar networks in social and exact sciences. They refer only to an outdated experience by the National Aeronautics and Space Administration (NASA). Recently, major advances have been made in techniques to ease the interfacing of disparate parts that are contributed by partners with different interests.