I'm wondering if it would work for corn? Lots of farmers in NE are late planting corn 'cuz the fields are too soggy. Does corn need to be put in the ground?
I have worked a job where we were aerial seeding corn. The farm was completely flooded out after emergence, but in order to get the Federal Crop Insurance, the farmer was required to 'try again'. Unfortunately, it was still too wet to get tractors in to re-plant, so they called us in with the AT-402. They had several bulk wagons of seed and we would fill the hopper over the top. It wasn't a very 'exact' science. The pilot can adjust the dump gate from inside the cockpit, but it takes a few loads to get it calibrated like it needs to be. Luckily, the farmer had scales on his wagons and we could keep track of how much we loaded. X lbs should cover X acres.
While waiting for the plane to return, I asked the farmer if he had any estimate what our plant population was going to be. He did some quick and dirty math and decided that, if we had 100% emergence, they would have somewhere around 200,000 plants/acre. Normally, farmers are planting anywhere from 32,000-40,000 plants/acre. Basically, we were putting it on thick enough that you could walk across the field without getting your shoes muddy.
We did some foliar feed spraying for the same farmer later that summer and I asked him how the corn turned out. He said it actually came up, but due to the extremely high population, it only got about 4' tall and never really had any ears to speak of. They said they were expecting that to happen and cut the corn for silage.
As for covering the seed: There is a lot of 'down pressure' coming from the back of the wings. When seeding soybeans due to wet conditions a few years ago, the beans where 'thrown down' so hard and the ground was wet enough that the seed pretty much covered itself. They did have decent success with soybeans that year.
The problem with aerial seeding corn comes at harvest time. Combines used for shelling corn don't actually 'intake' the stalk (ideally). They simply pull the stalk down between two rollers, and the ear pops off and enters the combine. If the corn is broadcast planted, there is no way to efficiently funnel the corn stalks between the rollers without severe stalk breakage and ear loss.
