I tried various pneumatic launchers when I lived in a rural area on a lake front, including a gas propelled spud/tennis ball gun. Fun, but they all make some noise. No longer practical now that I live in town.
For expedient launching of receive-only antennas, I use a sling. Not a slingshot with elastic bands, but the ancient style rope or string type sling. In urban and semi-urban areas, using anything that resembles a weapon would be inadvisable. With the sling it takes only a few quiet, discrete whirls and off it goes.
I use heavy duty fishing line, usually the flat ribbon type I use with bass fishing through weeds - it resists tangles and birdnesting. The weights are improvised, often a small soft plastic pill bottle left over from vitamins or ibuprofen - the white HDPE bottles are durable and soft enough to cause no damage when they hit something. I fill 'em halfway with coffee grounds, sand, whatever's handy.
This trick is good enough to get a receive-only random wire - usually very thin magnet wire - up a tree or across a roof in a few minutes. Works great at the local parks too for getting some wire in the air to improve reception with a portable. The fishing line and plastic bottle for launching reduce the risk of electrical shock if the line happens to cross an unseen power line - occasionally a risk in any urban or semi-urban area, tho' so far I've managed to avoid that risk by scouting carefully beforehand using binoculars. After the fishing line is satisfactorily high enough, I'll attach the antenna wire to the end and use the fishing line to drag it up the tree. I hitch the other end of the fishing line, with the pill bottle, around a tree trunk, fence post, whatever's handy. From 20 yards or so away it's all virtually invisible to casual glances.
Might be adaptable to field expedient transmitting antennas, dunno, haven't tried it.