Once the township gave their OK, Gleim backfilled the hole. They took a little longer to fill in the hole and used a shaker to tamp things down as they went. They also brought in a load of fresh top soil to level things up and provide a good base for a new lawn.
Heather and I spent the rest of the week raking the area level, spreading fertilizer and grass seed, and keeping things moist with the sprinklers until I could get some straw spread on top.
It won't be long and no one will be able to tell that an airplane came out of that small window.