Continuity mistake: When Clark blows out the barn doors, they go out at a fairly low angle to the ground. But when they come down next to Lois they drop down straight out of the sky.
Suggested correction: The pieces of the barn and door blown off are on screen for a second or less and don't travel far enough on screen for you to predict their trajectory. They could have easily been moving upwards without being able to tell. The barn door travelled far enough that it would have risen higher into the air.