The air combat in Xenonauts is initiated when one of your interceptor squadrons closes to attack range with a UFO on the strategic map (or vice-versa, if you are unlucky). It takes the form of pausable real-time combat between up to three combatants on each side, seen from a top-down perspective. The aircraft are the same ones controlled on the strategic map, carrying the weapons you specified when you equipped them at base. If they are damaged or destroyed in combat, they are damaged or destroyed on the strategic map too. The same applies to ammunition and fuel levels as well, so your interceptors are unlikely to survive being ambushed by UFOs when returning to base from a mission if you’ve fired off all their missiles and spent most of their fuel.
In the combat, there are two types of weapon. Rapid-fire weapons have fire arcs (shown on the screen) which the enemy must be within in order for the weapon to fire. These hits are assigned based on the weapon accuracy percentage rather than the position of the target, assuming it is within the fire arc. Missiles work differently. They must be be in range and locked onto a target before they can be fired, but hits are calculated based on the position of the target relative to the missile. In short, this means you can evade them if you have a sufficiently agile craft.
Certain types of both aircraft and UFO can perform special actions which can give them an advantage in combat. For instance, human F-17 interceptors and light UFOs can perform a ‘canopy roll’, which essentially allows them to strafe either left or right and is extremely useful when evading incoming fire (particularly missiles). These special abilities are on cooldowns, so must be used wisely. They also cost extra fuel, the universal currency of air combat in Xenonauts. The interceptor fuel level, less the distance to return to base, is imported from the strategic map. Fuel is burned rapidly in combat, so it is always a race against time to destroy the UFO before your aircraft are forced to disengage and return to base. Engaging the enemy on the very edge of your operational range is a risk, but if you’re fighting the aliens close to your base you’ll have plenty of fuel to burn on special abilities!
There are over a dozen types of UFO in the game with different stats, weapons and fire arcs, each requiring different tactics to defeat – air combat in Xenonauts should be a whole new challenge for even experienced X-Com veterans!