I agree with Palin Dromos. I think Clark's power of flight will emerge when he is forced to save either Lana or Chloe from being sucked up into the tornado. It won't be a power he can maintain like the others yet. It will come as a surprise to him, especially since he can't seem to get it back. Why he was able to fly when the twister struck and not after could be a mystery subplot that runs throughout the show.
When life hands you lemons, ask for Tequila and Salt.
Make like Rick Blaine and make her go on the plane. It's the right thing to do.