NextSimFlight: simplicity
Minimal interface, one button, one route: NextSimFlight excels when you want to take off fast. Filters are deliberately limited and the site is English-only.
It is the right choice for an improvised session with no particular preparation.
Where2Fly: weather and coverage
Where2Fly shines at choosing a destination based on weather and scenery coverage, with fine-grained filters and a public API. The trade-off is a denser interface and longer loading times.
Pick it if you choose flights based on real weather or the sceneries you have installed.
RFD: modes and preparation
RFD covers four modes (real, LIVE, AI, fictional), seven languages, live ADS-B traffic, IFR/VFR charts, briefing and SimBrief export in a single workflow.
Its strength is the chain: route, weather, charts, export, without switching tabs or rebuilding the route elsewhere.
What RFD does not do (yet)
No weather filters as advanced as Where2Fly, no public API, and no community scenery selection. These gaps are deliberate: RFD focuses on generation and preparation.
How to choose
Improvised 30-minute session: NextSimFlight or RFD with no filter. Destination driven by weather or sceneries: Where2Fly. Prepared flight with SimBrief export, multiple languages and LIVE tracking: RFD.
All three are free for their main use. Nothing stops you from combining them.