lemongrove
They can ( should) be wearing masks.They are not facing each other on the bus either.
Do you honestly think that children on a bus are all going to remain facing in the same direction for the whole trip? Or not touch each other? It doesn't matter anyway if the bus isn't well-ventilated because the air will be full of Covid droplets, if an infected child isn't wearing his/her mask properly.
Sorry, but school buses are an additional risk, which parents will avoid if at all possible.