Ooops sorry, I thought I had edited those out from the mission.sqm.
I have updated the original d/l link.
I suppose it would be possible to use createUnit to silently spawn paratroopers, but I think there are issues will getting the units to start with chutes open.
Another solution would be to create a group of paratroopers in the mission editor, and set their Special to Flying. In their init fields put this setPos [(getPos this) select 0, (getPos this) select 1, 5000]. In the leader's init put grp_para1 = group this ; this setPos [(getPos this) select 0, (getPos this) select 1, 5000]. Starting at 5000m they will take hours to reach the ground and will not be visible. Also put a game logic on your map named server.
Put a trigger on the map and in the On Activation field put [this, grp_para1, thisList select 0,50,200] exec "moveparas.sqs".
Then the script moveparas.sqs:
if not (local server) then {exit}
_pos = getPos (_this select 0)
_grp = _this select 1
_target = _this select 2
_range = _this select 3
_height = _this select 4
_posx = _pos select 0
_posy = _pos select 1
{_x setPos [_posx + _range - 2*(random _range),_posy + _range - 2*(random _range),_height - (random 20)]} forEach units _grp
@(((getPos leader _grp) select 2) < 5)
~10
_grp setCombatMode "RED"
_grp setBehaviour "COMBAT"
_grp setSpeedMode "FULL"
_grp setFormation "VEE"
_grp move getPos _target
~10
;again for paranoia's sake
_grp move getPos _target
exit
When the trigger is activated the para units will be moved to random positions around the trigger centre. The 50 sets a scatter of 50m about the trigger centre, and the 200 sets the height of 200m. A random 0-20m is removed from the the height for each unit so that they are not all at the exact same height. When the units have landed they advance to the last position of one of the units that activated the trigger. Instead of the thisList select 0 in the trigger activation field you could put the name of a game logic, say gl_para1, to which you want the units to advance.
I am "at work" so of course all this new code is untested.