Let's see... they developed a way to hide a bomb powerful enough to bring down an airliner inside a laptop, but not a way to buy tickets for flights other than a few specific routes on a few specific airlines? If you believe that, I've got a bridge to sell you.
I know some (maybe even most) of the affected airlines have significant government ownership. It could therefore be a way of gaining political leverage.
It could also be a leg-up to American carriers competing on those routes. Another commercial option is a tactic to require implementation of security practices that involve American-made equipment.
I'm sure there are many other possibilities that make more sense than the public explanation, which only seems to make sense if we assume the people protecting us are incredibly stupid. I don't think they are, so the public story is probably just a cover.