Try:
String exePath = Path.Combine(Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location),"AIRApplication", "COMTEST.exe");
The above code resolved 1/2 of the issue. The other 1/2 was that the exe was not being copied to the debug folder. Updating the ‘Copy to Output Directory’ option resolved this.
6
solved Running an executable that is inside the project