I don’t think it needs a self destruct device. It simply needed to be programmed NOT to land in enemy territory. This craft is a technological marvel yet they neglected possibly the most obvious detail.
I have a feeling that with all the flaws/viruses they are encountering, that such a program would blow up too many planes.
Failsafe mode is common in most automated equipment.
If it "autolanded" it probably ripped its landing gear off and damaged the underside, hence why they covered it up.