CIA Assets

When you read things like this:

For instance, what should we make of the fact that, less than three weeks after Atta and Marwan Al-Shehi enrolled at Florida's Huffman Aviation, a Lear jet owned by school financier Wally Hilliard was seized by DEA agents with 43 pounds of heroin onboard? It was the biggest seizure of heroin ever in central Florida, and yet Hilliard was not charged.

...and knowing the intimate relationship between the CIA and the drug trade--- I think it is fairly safe to say the 9/11 hijackers were CIA assets or were under CIA control in some way.

Assuming the CIA was handling the hijackers prior to 9/11, exactly what plans did the CIA have for the "hijackers"?

This is a really critical question.

--Was the CIA simply watching the hijackers?

--Were they setting them up in some kind of sting operation that went awry?

--Were they setting them up to be fall-guys when somebody else was doing the real hijacking?

--Were they actively helping them commit the hijackings?

The first possibility seems least likely and I think the last possibility is most likely. However it is not clear that they could recruit these men knowingly to be suicide hijackers. So there was clearly some double-crossing somewhere-- either by the hijackers or by the CIA. It's hard to know at this point without understanding the plot better. However, again my tendency is to think the CIA was using the hijackers, and not the other way around.