if you read carefully the doc
AIR now supports this on an experimental basis, with the packaging of the libraries for each of the four supported ABIs into the single AAB file. This uses a different resource packaging tool, “aapt2” as well as the “bundletool2 utility which are now added to the AIR SDK (see license information for these under the “lib/android/licenses” folder).
emphasis mine, expect the production of AAB to fail, stop considering it as an available feature
To generate an Android App Bundle file, the ADT syntax is similar to the “apk” usage:
adt -package -target aab <signing options> output.aab <app descriptor and files> [-extdir <folder>]
and related to your error message
flags should start with – indicate a bundletool error
see for ex Command unzip out.apks -d apks not working ?
eg. a flag
n was used with a single dash
instead of a double dash eg.
now look at this post Announcement: If you ask for help about code
you don’t mention which OS you’re using, which version of the SDK, how you run it on the command-line, you don’t provide your full error output, etc.
I call that bullshit here, the double dash
-- is something regularly mentioned in command-line tools
see POSIX 12.2 Utility Syntax Guidelines
The first – argument that is not an option-argument should be accepted as a delimiter indicating the end of options. Any following arguments should be treated as operands, even if they begin with the ‘-’ character.