As one who has used one, I'll vouch for its effectiveness in cooling things down on a hot day. You do have to get ice on the way to the airport and there has to be liquid water with the ice for it to work.
I'd fire it up on the ground and use it until things cooled off at altitude (if they did). Usually would shut it off and then start it again during the descent for landing and taxi in.
It's not a swamp cooler with all the humidity of those things. It blows cool air. Weight loaded is about 30 pounds, as I recall.
