On Android and IOS tablets, you click Flight Plan - More Options - Share With Local Devices. This is the tablet that has the flight plan you want to share.
On the other tablet, you click Flight Plan - More Options - Accept Flight Plan.
Both tablets must be connected to the same router. The tablet with the flight plan can be the router if it has a hot spot feature.
I don't know if this works with the IFly device, but I assume it probably does.