No specific locale was mentioned in most of the reports I read, but one does break it down by section:

Furthermore, says Travis, the Pacific Northwest, the Midwest, and the Northeast—areas of the country typically blanketed with aircraft contrails in mid-September—showed the largest changes in diurnal temperature range, mostly from increased daytime high temperatures

http://www.sciencenews.org/articles/20020511/fob1.asp
and:
http://archives.cnn.com/2002/TECH/science/08/07/contrails.climate/



>>>But there was no demand. The roads were rather empty. Nobody traveled much unless they had to.
>>
>>Interesting. I never knew that. BTW, it's roughly £0.95 per LITRE here at the moment!
>>
>>Reduction in travel: I saw a docu a year or so ago, about global cooling, and how it's helping to mask the full effects of global warming. The vapour trails of airliners actually have a marked effect on terrestrial temp. During the 3 days or so after 9/11, when aircraft were grounded, the temp. over NY rose by several degrees, without the criss-cross contrails everywhere.
>
>Mmmm... NY of that week is the best place to get slanted statistics, with all the things which were out of the normal - different traffic patterns, smoke/dust in the air etc etc. I somehow doubt that the jet exhaust is beneficial to anything but the owners' pocket, and maybe postcards (can't have nice sunsets with clean air). Are there any wider statistics, to cover all of the States and maybe Canada for that week?