Hi,
Erin is right. Xanax, which is a member of the benzodiazepine family, does not require time to build up in your system. Very effective in dealing with anticipatory anxiety. Antidepressants, on the other hand, require time to build up in your system in order to become
therapeutic.
In terms of operating a car, there is a warning placed on the bottle to avoid driving a car or operating machinery.
Speaking for myself, I do take Ativan prior to flying in order to cope with my anxiety and have found it extremely helpful. By the time I get to my destination any sedation has typically worn off.
This is something that you should discuss with your PCP. He/She may be willing to give you a test dose so that you will know what your personal reaction will be.
Hope this helps,
Mittens