I've been on three flight since the attacks in afganistan (including one on the day it happened) and noticed no significant change in security, except maybe that the screening personnel seemed a little more awake than they ususally do. And curbside check-in (which is usuaually the first to go during a security crackdown) was still in effect. But, IMHO, security lines have been long since the FAA increased the sensitivity of the metal detecters after the Oklahoma bombing (since then I have had to take my watch off to get through detecters).