I'm not sure if there is a specific simulator for FANETs, but I recommend you modify VANETs Simulators which are well developed and successfully tested.
For example VNS is a simulation framework that completely integrates the mobility and network components in a transparent and efficient way. The mobility model of VNS is based on DIVERT, a microscopic traffic simulator. You have to change the mobility model to UAV case. You might need a basic knowledge of Linux, Python and C++.
We have just released an Aerial Vehicle Network Simulator (AVENS) which main purpose is to provide means of simulating UAV networks (FANETs) integrating OMNeT++ Network Simulator and X-Plane Flight Simulator.
Please, refer to the attached publication.
https://www.lsec.icmc.usp.br/avens
Conference Paper AVENS – A Novel Flying Ad Hoc Network Simulator with Automat...
How to change add movement of Drones in Omnet++(Currently I haove Linear motion for Cars).I want to use RandomWayPoint Mobility model.How to implement RandomWayPoint Mobility model?
You could look at https://support.tetcos.com/support/solutions/articles/14000121929-netsim-matlab-interfacing-for-uav-drone-flying-adhoc-network-simulations