I have created a new unit: the fighter.

Comparison

Relative to a tank, a fighter is very fast, has a slightly higher attack strength, and can see more terrain. This comes at a cost. A fighter takes longer to build, and it crashes if it runs out of fuel.

New mechanic: unit builds

Click on any of your team's cities.

In this city, we have one tank within the city. The city is partially done building another tank, and the new tank will be ready in three days. Click on the wrench/gear to choose a different unit.

Here you can choose to build a fighter instead Click on the wrench/gear next to the fighter.

Now the city is building a fighter. It will be ready in 6 days.

New mechanic: fuel

Fighters use one fuel for every square they move. They refill their fuel by landing in cities. Landing costs them one additional movement point, and restores them to their maximum fuel.

To help you track how much fuel is left, I added a gray box outline that extends to half the remaining fuel range, and an orange box that extends to the full remaining fuel range.

If you see the orange box getting near your city, it is time to move your fighter back to the nearest city. This fighter has just enough fuel to make it back to a friendly city.

If you don't have enough fuel to get back, your fighter will crash. Is there an enemy nearby that you can attack?