As Tom already said, the category should be Airport Overview only, as the airport is the only subject of your photo. Therefore, no details of the aircraft FROM which you made the photo should be listed (unless in the Remarks field), because a viewer who selected an aircraft type or airline or registration in a selection menu, would see a picture of an airfield instead of the expected picture of that aircraft type, airline or registration!
As Tom said, the editors have a special Window Views Manual which lists all possibilities, but we feel that it is way too complicated for general uploaders use.
But we have taken your point that the current Window View Read Me wasn't too helpful, so we have written an updated version. It will be placed asap on the upload page, but in the meantime you can read the new text here already:
Window View Read Me
A shot from inside the aircraft cabin through the window.
If parts of the aircraft (wing) are included, list the details of the aircraft (type, airline, registration, cn, code) in the appropriate fields.
If the photo shows an airport and also parts of the aircraft, list the aircraft details and additionally mark the Airport Overview category too.
If no parts of the aircraft are included, but the subject of the photo is an airport, do not use Window View, but mark Airport Overview only, mark the aircraft and airline field with a minus (-), and leave the registration, cn and code fields blank. The basic rule in this case is: list the details of the subject of the photo, not FROM where you made the photo (listing aircraft details in this case would result in the viewer seeing a picture of an airport while he clicked on and expected to see a photo of an aircraft type or airline, etc.).
If some other aircraft (e.g. air-to-air) is the main subject of the photo, list the details of that other aircraft, and do NOT select the category Window View.
Chief Database Editor