No military in the streets of Warsaw in 1988 except normal cadre members and soldiers on leave. Picturesque were groups of ex-soldiers (so-called "rezerwa") in civil cloths, with fancy self-made scarfs, drunk, returning home in groups and singing:
Godzina piąta minut trzydzieści
Kiedy pobudka zagrała
Grupa rezerwy szła do cywila
Niejedna panna płakała...
I'm not sure about security at the airport. Certainly nothing special. AFAIK, the martial law was abolished in 1984.