I recall reading in Straits Times (in mid-1980's) Mindef
revealed several flights of Soviet civilian airline, Aeroflot, had
veered off course while on approach to Paya Lebar (then our
civilian Int'l airport) and near Sembawang Airbase, possibly to spy
on it or test our response time in scrambling F-5's.
Also read a report in Janes Defence (from then) that Vietnam, which
was then an enemy of Asean as they had invaded Cambodia, had raised
questions about the size of our full (incl. all reservists)
military strength, saying it was a threat to them. Reservist
friends of mine told me they were sent to the Thai border for
military exercises during call-up at that time.
I'd say the threat of a Soviet-supported Vietnamese invasion was
real in that era. I think Asean had China (they supported the Khmer
Rouge, which were fighting the Vietnamese) on our side, so Vietnam
had to consider an enemy attacking from the north if they moved
southward.
