This settlement will only become available after the quest "Shadow of Steel". Prior to that, the airport will be overrun by ghouls. Take note that your settlers will wander inside the airport which will make it harder for you to round them up.
If you have Paladin Danse (or any other companion) stationed here, there will be times that they'll go missing but you'll hear them talking. To rectify this, create a bell (Resources > Misc > Bell), ring it once then fast-travel again to the same location. They should “appear” near the bell.
Also, your crafting options will be limited in this settlement. You can't build stores, watchtowers, settlement recruitment beacons, or plant crops to name a few.
Since the containers in this location will drastically change after the Brotherhood of Steel occupation, it's recommended to clear the area first of ghouls to maximize the loot.
(Pre-Brotherhood Occupation)