X-Plane - The world's most advanced flight simulator just got an upgrade. Download the free demo today for Windows, macOS, & Linux.
Worms - Worms is a Superb, Turn-based, Strategy, Online, Single and Multiplayer video game developed and published by Team17 Software Ltd.
FlightGear - The FlightGear flight simulator project is an open-source, multi-platform, cooperative flight simulator development project. It also simulates space flight in Earth's orbit. It's flight dynamics engine (JSBSim) is used in a 2015 NASA benchmark.
GunBound - GunBound is a Turn-based, Free to play and Online-Multiplayer video game developed and published by Softnyx.
Digital Combat Simulator - Digital Combat Simulator is a Free-to-play, Single and Multiplayer Combat Flight Simulation developed by Eagle Dynamics and published by The Fighter Collection.
Hedgewars - Hedgewars is a Free to play, Single-player and Turn-based Strategy video game developed by Hedgewars Development Team.