I was pretty nervous about it, but the flight attendants were great. The two year old would not keep his mask on for more than 5 seconds. The four year actually did better than we though he would and kept his mask on for part of the time.
We had plenty of snacks and whenever the we saw the flight attendants coming down the aisle we would start give them the snacks.
The flight attendants never said anything to us about the boys' masks.
Still, I don't think we'll fly again for quite a while. Not until things open up more.