we do a flour bombing comp at our club pretty regularly, it's surprisingly difficult from 500 feet to it a target,,,,,but incredibly easy to nearly hit a cessna,,,,go figure !
As for lollies ,perhaps they could be placed on the ground the day before and then have the kiddies look skyward as the plane flies over at 1000agl ,informing then ( at a time sufficient for said lollies to land ) that the little sweeties( the lollies not the kids) are out there for the taking,,,,,,,,actually to save fuel ( and the planet ) you could hold the event in the flight line of an airport ,,,the kids wont know , and think of the PR ,,,,QANTAS do lolly drops from a dash 8,,,, how cool
matty