Thank you for contacting Nike in regards to your product inquiry. Our customer service team provided me with your information so that I may assist with your product search.
From my understanding you requested the difference between the Nike Zoom VaporFly 4% and the Nike Zoom Fly. Please see below.
NIKE ZOOM VAPORFLY 4%
ZoomX cushioning for increased energy return
Carbon fiber plate
Weighs approximately 6.5 ounces
NIKE ZOOM FLY
Increased padding around the collar
Carbon infused nylon plate
Flywire reinforced eyelits
Weighs approximately 8.75 ounces
If you have any questions or concerns please contact Nike.com Customer Service at 1-800-806-6453 or respond directly to this email.
Elite Services Athlete
So, it looks as if both the plate and the midsole are made of different materials; only the Vaporfly has full carbon and Pebax.
Hope this helps; Happy 2018 :-)