4. [Richard] Clarke had been concerned about the danger posed by aircraft since at least the 1996 Atlanta Olympics... In 1998, Clarke chaired an exercise [that] involved a scenario in which a group of terrorists commandeered a Learjet on the ground in Atlanta, loaded it with explosives, and flew it towards a target in Washington, D.C.” (345) The Commission elsewhere concluded the description of this exercise by saying that the terrorist group “took off for a suicide mission to Washington” (457-58 n98).
Page 265
The 9/11 Commission Report: Omissions and Distortions
David Ray Griffin

This gets close to Dr Griffin’s target, in that we’re talking about an attack originating in the US. It’s not a commercial airliner, though, and isn’t a clear hijacking (though this depends on the meaning of “commandeered” here).

The example also falls short as far as we’re concerned, in that it relates only to Clarke’s exercises, rather than direct intelligence on what terrorists were doing. This is important because, for instance, we have no idea of how many other exercises Clarke might have done. We also don’t know how credible his speculations might have been to the military, although we can get some clues. This, for example, is the full Commission Report paragraph from which the Dr Griffin quote is taken (our emphasis):

Clarke had been concerned about the danger posed by aircraft since at least the 1996 Atlanta Olympics.There he had tried to create an air defense plan using assets from the Treasury Department, after the Defense Department declined to contribute resources. The Secret Service continued to work on the problem of airborne threats to the Washington region. In 1998, Clarke chaired an exercise designed to highlight the inadequacy of the solution. This paper exercise involved a scenario in which a group of terrorists commandeered a Learjet on the ground in Atlanta, loaded it with explosives, and flew it toward a target in Washington,D.C. Clarke asked officials from the Pentagon, Federal Aviation Administration (FAA), and Secret Service what they could do about the situation. Officials from the Pentagon said they could scramble aircraft from Langley Air Force Base, but they would need to go to the President for rules of engagement, and there was no mechanism to do so.There was no clear resolution of the problem at the exercise.
Page 345
9/11 Commission Report

The Defense Department didn’t want to contribute resources to his air defense plan? This surely confirms that they didn’t take the threat seriously, at least in 1996: precisely what the 9/11 Commission Report were saying. 

Clarke’s book offers further confirmation of this (our emphasis):

The Secret Service and Customs had teamed up in Atlanta to provide some rudimentary air defense against an aircraft flying into the Olympic Stadium. They did so again during the subsequent National Security Special Events and they agreed to create a permanent air defense unit to protect Washington. Unfortunately, those two federal law enforcement agencies were housed in the Treasury Department and its leadership did not want to pay for such a mission or run the liability risks of shooting down the wrong aircraft. Treasury nixed the air defense unit, and my attempts within the White House to overrule them came to naught. The idea of aircraft attacking in Washington seemed remote to many people and the risks of shooting down aircraft in a city were thought to be far too high. Moreover, the opponents of our plan argued, the Air Force could always scramble fighter aircraft to protect Washington if there were a problem. On occasions when aircraft were hijacked (and in one case when we erroneously believed a Northwest flight had been seized), the Air Force did intercept the airliners with fighter jets. We succeeded only in getting Secret Service the permission to continue to examine air defense options, including the possibility of placing missile units near the White House. Most people who heard about our efforts to create some air defense system in case terrorists tried to fly aircraft into the Capitol, the White House, or the Pentagon simply thought we were nuts.
Page 131
Against all Enemies
Richard A Clarke

In Clarke’s Commission testimony he didn’t seem surprised at the lack of recognition of the threat, even in 2001.:

MR. BEN-VENISTE: Given the fact that there was a body of information with respect to the use of planes as weapons within the intelligence community's knowledge, had you received information about Moussaoui training to fly a commercial airplane? Would that have had some impact on the kinds of efforts which might be made to protect commercial aviation?

MR. CLARKE: I don't know. The information to which you refer, information in the intelligence community's knowledge about al Qaeda having thought of using aircraft of weapons -- that information was old, relatively speaking -- five years, six years old -- hadn't recurred to my knowledge during those five or six years, and has to be placed -- to give the intelligence community a break -- it has to be placed in the context of the other intelligence reports. The volume of intelligence reports on this kind of thing, on al Qaeda threats and other terrorist threats, was in the tens of thousands -- probably hundreds of thousands over the course of five or six years. Now in retrospect to go back and find the report six years earlier that said perhaps they were going to use aircraft as weapons is easy to do now. But I think the intelligence community analysts can be forgiven for not thinking about it, given the fact that they hadn't seen a lot in the five or six years intervening about it, and that here were so many reports about so many other things.
http://govinfo.library.unt.edu/911/archive/hearing8/9-11Commission_Hearing_2004-03-24.htm

The mention of “probably hundreds of thousands” of intelligence reports helps to put Dr Griffin’s 15 examples (these 9 plus 6 more later) into context. (Although note that he did go on to say that he’d like to think he could have put the pieces together, if he’d known about Moussaoui.)

This particular example does cover suicide attacks that originated in the US, then. But on the other hand, it doesn’t come directly from intelligence, or relate to passenger jets, or necessarily to hijacking, and it doesn’t appear Clarke’s efforts were taken seriously at the time (by the military, at least). And as such it seems to support the official NORAD position, more than hurt it.