Today's grounding did create some ripple effects, and between 10 am and 2 pm today, there were slightly more delayed flights (538) than during the same period yesterday (447). But with United inching back toward its original schedule, there were 535 delays between the hours of 11 and 3 pm today, compared with 540 yesterday.
Source:
http://www.vox.com/2015/7/8/8914821/...-flight-delays