…until after gaining flight (and even then).
Granted, when we approach a film based on a preexisting property, as an audience we bring the baggage of expectation, but it is unfair to criticize the character’s in-film choices for abilities that haven’t been established. The film gives us a clear precedent for Clark developing his powers later than he is potentially capable of and later than tradition with flight.
Consider the following sequences which go differently if Clark has enough speed to avoid detection and identification: