That was only a local effect, in densely populated areas. And it wasn't cooling; it was a reduction in the variation between day and night. As reported at the time:

https://edition.cnn.com/2002/TECH/science/08/07/contrails.cl...

And even that much appears dubious:

https://www.bbc.co.uk/blogs/climatechange/2009/05/911_contra...