Really ?
I thought they'd have a few turboprops left and that would be it. Nearly 30 years after such a catastrophy and with limited domestic and global industries restored, I severely doubt anyone would have the spare parts or time to start repairing or building jets.
I think that it depends on how much the planes are used and how important it is considered to keep even a small number of them operational as long as possible. If they for some reason want to fly a lot with a (comparatively) lot of planes in the 80s, I doubt planes would survive even beyond the early 90s. On the other hand, if only a small number of planes of one or two types is in use, and only a few hours per month/year, then the rest could be kept in storage and that might mean some could remain serviceable into the 2000's.
Sweden will have retained some capabilities for building and maintaining aircraft, and could help with keeping at least some of the Drakens flying. And the Vinka is a domestic product and if the plant that made it survived, even new parts for the planes could be made for some time. There would be also capabilities to maintain the Hawk as it was built locally. They would also have at least some stocks of spare parts at Halli for different planes, especially the Vinka and the Hawk.
The main problem might be with parts that don't "keep" but would degrade naturally over time, even if not in use, and could not be obtained anywhere. Not being an expert I don't know which parts these would be, though. At least things to do with the electronic systems, I'd imagine. Also obtaining the right fuels, oils and soforth would present problems.
Maybe someone with more expertise than me could weigh in?