If a customer is not able to find a recent airgap download release, it is usually because their license is pinned to a specific release. The license must be unpinned to reveal the newer releases.
By default there will be no more than one release shown that is older than the date the license was created. In order to show all releases since the beginning of a channel, add the show=all parameter to the URL. Note that this parameter will not override a pin to show newer releases in a channel.
The UI also filters out all optional releases that are older than the newest required release. The show=all parameter will make these optional releases visible.
Another reason releases may be missing from that page is that the airgap build failed or did not run for that release.