Plancher had 65 yards on eight carries and Ford picked up 61 yards on 15 carries.
Matt Grothe went 6-for-8 passing for 96 yards and a pair of touchdown passes to Jessie Hester for South Florida.
Cade Thompson was 6-for-19 for just 25 yards and an interception and Dontell Miller scored the only touchdown for the Skyhawks on a fumble recovery. Daryl Bourne had eight carries for 37 yards in the loss.
Notable deaths of 2014 [PHOTOS]
Arizona Cardinals player formally charged