AirSim was originally created by Shital Shah during late 2016. Shital authored physics engine, multirotor model, car model, environment models, sensor models, all Unreal Engine related code, APIs, SimpleFlight firmware, computer vision components, documentation etc.
Chris Lovett, another original author, contributed the MavLink communication library, PX4 related components, Settings system, build system, several important bug fixes and so on.
List of all contributors since our first release in February 2017 can be found here.