I could use the same way compile an swf with mxmlc and amxmlc:
amxmlc -load-config obj\config.xml
mxmlc -load-config obj\config.xml
But, What is the difference?
It seems there is no functional difference between those.
Adobe's "Building Adobe AIR Applications" document says this about the difference between amxmlc and mxmlc:
The only difference between the Flex and the AIR versions of the utilities is that the AIR versions load the configuration options from the air-config.xml file instead of the flex-config.xml file.
Adobe's "Using mxmlc, the application compiler | About the application compiler options" document says this about load-config :
Specifies the location of the configuration file that defines compiler options.
If you specify a configuration file, you can override individual options by setting them on the command line.
All relative paths in the configuration file are relative to the location of the configuration file itself.
Use the += operator to chain this configuration file to other configuration files.
Adobe's "Flex compilers | About configuration files" document says this about load-config:
You can, however, create a custom configuration file and pass it to the Flash Builder compilers by using the load-config option.