AIR is Automated Image Replication.
It is part of the SLP process and utilizes the OST API to replicate the data from one Master to another and merge it in the catalog. It does it in such a way that the import is lightning quick. Once it's imported on the remote master, it's a backup image like any other.
Two issues with the suggestion - first, AIR has to be configured on the front end of the backup. Once it's backed up you can't retroactively add steps to the SLP process.
Second, the hardware has to be OST capable and also have support for AIR. I don't know if DDRs support AIR yet or not. As of about 2 years ago they didn't. Either way you would need one on the source side and one on the destination side
Dan's suggestion of just leaving it and shutting down your old environment until needed makes sense and is probably the easiest. I would recommend making backups of your catalog and keeping it handy in case it does't come back up. Otherwise, you can import anything on the old tapes and import them into your new environment if you want to go through all that trouble.