This is a masterclass in how to handle a software issue in 1998.
Airbus: Hey, lets burn CD Roms and USB thumb drives and sneaker-net the software on to 6000 planes across the planet.
This should work like Tesla firmware. Every plane has a version number on its firmware, and when an update happens the version is incremented. The planes routinely ping for updates (say every power up), and download non-critical updates when at gates with wifi. On safety critical updates, there are private networks (not to mention in-flight wifi these updates could piggyback on). Once an update is downloaded, pilots should be able to hit the update button the moment the plane is back at a gate.
The real issue is that if you have to sneaker net updates onto planes, airlines just wont update. This patch was absolutely mandated by the FAA but think of how many updates are probably not. There might be many vulnerabilities and errata bug fixes on countless libraries these softwares depend on. Device firmware, flight control computers, zero day vulnerabilities, communication packages to cross talk with other on-board systems, etc etc etc... Not to mention fixes in core components like the kernels (I wouldn't be shocked if these planes ran some flavor of Linux and X11 or Wayland for flight panel displays.
We know from other industries if updates are a manual process, people will leave what they think is *good enough* alone out of laziness or cost. So while I laude Airbus here for their seeing a problem and responding to it, I fault them for the shit way they update planes. How many aircraft are running really old software?