why don't we have the ability to fly?not because of the natural science but related to powers.
because of the way our skeletal system is made, its impossible for humans to fly
There is an ability in human race which has no parallel in any other race - The ability to think analyse and invent/create. This ability overcomes all other apparent disabilities as compared to other species. The brain power thus becomes more than the bran power and enables a man to fly using his invention.
Otherwise physically, humans are not a flying species due to absence of the wings that can support the weight as have the birds and bats etc.