I haven't changed my flight plans due to war, etc (more so due to UA's new SWU/Hfare policy!). I'm still flying & will continue to do so. If I had a trip to Asia (I don't), I would rethink that due to SARS & perhaps postpone until it seemed to be more handled/under control, especially because of the potential quarantine issue. Can't be out of commission for that length of time.
Frequent flyers aren't really going to change their travel plans that much; leisure travelers are more affected by the media, misconceptions (I'm always getting the 'doesn't it take a couple of hours to get through security now' comment/question), generic fears. I've had a boatload of friends tell me they're not flying overseas this year or postponing trips because of war, worries about terrorism, how we'll be treated overseas.
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Sharon