Have you unlocked the relevant tech tree items?
You need to “research” a commercial licence
This unlocks the ability “research” an extended commercial licence and night flights (separate research projects).
Once you have the extended commercial licence you can “research” the medium aircraft permit.
When you get the medium aircraft permit you can build medium aircraft structures (runways stands etc.)
To get to large aircraft you need to get the ultimate commercial licence and then the large aircraft permit
To unlock runway lights, you need to research night flights and then the “advance runway lighting”.
This blog post explains the R&D process.
Someone has also posted an image of the tech tree unlock dependencies somewhere.