unitname setPos [getPos unitName select 0, getPos unitName select 1, (getPos unitName select 2) + #]
where # is the number of meters you want the unit to go up into the air.
My suggesting is write a script that looks like this:
_unit = _this select 0
_unit setPos [getPos _unit select 0, getPos _unit select 1, (getPos _unit select 2) + #]
Exec it with:
[this/unitname] exec "scriptname.sqs"