What if air defense technology improved a bit during the last 36 years?

Not sure, but I'd wager it was shot down using their 358 missile (aka SA-67). The missile can be fired from a rail on a truck and will patrol an airspace for a time until finding a target using an infrared seeker. Since it uses an infrared seeker (combined with it being fairly small), makes it incredibly difficult be detected by radar, while stealth tech is a fairly useless counter measure.