Why can't clark fly?

Answer 1

In the Smallville series, flight is a natural power for all Kryptonians however Clark was not capable of using the power of flight like all other Kryptonians (including Kara and Zod were) because in the Smallville series flight is seen as a superpower in which a Kryptonian has embraced their own history and heritage as a Kryptonian.

Answer 2

he hasn't learned yet