: Build runways with a minimum length of 25 units. These must be connected to your taxiway network so planes can reach the stands.

: Unlocks at the Megalopolis milestone.

: Requires reaching a specific milestone (varies by map) to access the Airport Area tool. Building a Modular Airport (Airports DLC)

To create a custom, expandable airport using the specialized DLC tools, follow these steps:

Setting up a functional airport in Cities: Skylines requires different steps depending on whether you are using the or the base game's Pre-Built Terminals . Installation & Activation

: Use the Airport Area Tool to paint a district over the land where you want the airport. This automatically levels the terrain within that boundary.

: Ensure the Airports DLC is purchased and installed via Steam or your platform's store. Milestone Requirements : Base Game Airport : Unlocks at the Metropolis milestone.