Updated

This is a partial transcript from "Your World with Neil Cavuto," August 10, 2006, that was edited for clarity.

NEIL CAVUTO, HOST: With reaction now from the White House, we are joined by Frances Townsend, the assistant to the president for homeland security and counterterrorism.

We dodged a big bullet here, obviously, Ms. Townsend. The question is, what kind of bullet? What were these guys planning? Have you learned anything more?

FRANCES FRAGOS TOWNSEND, WHITE HOUSE HOMELAND SECURITY ADVISER: Well, as you — as you know from Secretary Chertoff's announcement this morning, and from the statements, frankly, from British officials, who are closest to the investigation, multiple simultaneous attacks, using improvised explosive devices on planes crossing from the U.K. into the United States.

We believe that they would have waited until all the planes were in the air, that they would have exploded them near simultaneously, to get the greatest amount of casualties.

You know, the Brits put it the best today, when they said, this was a plot of mass murder.

CAVUTO: Let me ask you this about this idea that they might have been planning a dry run as soon as a couple of days from now. What — what have you learned about that?

TOWNSEND: Well, you know, Neil, it would not surprise me for us to learn that they were — that they were going to do a dry run.

I — I think it is fair to say that that is part of sort of the terrorist tactics. They want to be sure they can get devices and component pieces on, so that the attacks — they can assure success.

I — I would rather — I think we are not in a position right now to say when they would have done that or that they were definitively going to, but it is certainly consistent with the — with the planning for terrorist attacks that we have seen in the past.

CAVUTO: Do you think that this is still a real and constant threat, that, again and again and again, it comes back to the airlines, the airlines, the airlines?

TOWNSEND: They are clearly obsessed with airlines. You know, you have heard a lot today, and on various talk shows, about the Bojinka plot, going back to the mid-'90s...

CAVUTO: Right.

TOWNSEND: ... multiple aircraft traveling — traveling across the Pacific.

We know that they are obsessed. They were obsessed on 9/11 with aircraft, and they continue to be obsessed. They define — re — refine their techniques, to see if they can get things that will get past screening measures.

And, so, we constantly try to stay ahead of them. This is one, gratefully, with our work with the Brits, we were able to get ahead — stay ahead of them to ensure the safety of the flying public.

CAVUTO: But a lot of that flying public, ma'am, as I am sure you would be well aware, is — is rethinking their — their summer travel, or what's left of it, even fall travel plans, many thinking, all right, now the security lines are going to be little longer; I — I can't take anything liquid on the plane.

They might be canceling reservations.

In a way, then, do the terrorists succeed by not succeeding?

TOWNSEND: Well, you know, they — if people begin to cancel their reservations and not travel, the — the terrorists do, in some measure, succeed.

You know, this is about fear. It's about instilling that fear in the flying public, both British and American.

And you heard, today, the president, and you heard Secretary Chertoff say, the measures we are taking, while they will create an inconvenience for the flying public, is the — are the very same measures that ought to give them the reassurance that it is safe to continue flying.

CAVUTO: All right, Ms. Townsend, thank you very much — Frances Townsend, the president's special assistant on homeland security, in Washington.

Content and Programming Copyright 2006 FOX News Network, Inc. ALL RIGHTS RESERVED. Transcription Copyright 2006 Voxant, Inc. (www.voxant.com), which takes sole responsibility for the accuracy of the transcription. ALL RIGHTS RESERVED. No license is granted to the user of this material except for the user's personal or internal use and, in such case, only one copy may be printed, nor shall user use any material for commercial purposes or in any fashion that may infringe upon FOX News Network, Inc.'s and Voxant Inc.'s copyrights or other proprietary rights or interests in the material. This is not a legal transcript for purposes of litigation.