Yes, all registrars who wish to make transactions with the .aero registry must be authorized by SITA, Sponsor of .aero registry and then successfully complete OT&E certification with the registry operator Afilias.
Completing the OT&E process will help ensure that your system will function properly, which safeguards your .aero revenue. If you are a .ORG or .INFO accredited Registrar you will only need to complete a .aero specific OT&E test, as your client is currently EPP RFC compliant. Please see the following question, "How do I begin the OT&E certification process?" for information on how to become certified by SITA.