While that was designed in 1984, the US DoD had successfully tested laser weapons over a decade earlier:
'The first was in 1973 when the USAF shot down a winged drone at their Sandia Optical Range, New Mexico, using a carbon dioxide GDL and a gimballed telescope. Subsequently, in 1976, the US Army employed an electrically pumped HEL to destroy a number of winged and helicopter drones at the Redstone Arsenal in Alabama. The USN, in March 1978, then engaged and destroyed an Army TOW missile in flight' [1]
The first targets destroyed from an airborne platform (KC-135) were in 1979.
I think this one would be an even better reference point to show the gulf of effectiveness between where we were and where we are now: http://en.wikipedia.org/wiki/NES_Zapper
'The first was in 1973 when the USAF shot down a winged drone at their Sandia Optical Range, New Mexico, using a carbon dioxide GDL and a gimballed telescope. Subsequently, in 1976, the US Army employed an electrically pumped HEL to destroy a number of winged and helicopter drones at the Redstone Arsenal in Alabama. The USN, in March 1978, then engaged and destroyed an Army TOW missile in flight' [1]
The first targets destroyed from an airborne platform (KC-135) were in 1979.
[1] http://www.ausairpower.net/APA-DEW-HEL-Analysis.html