Hello Pete.
We don't have clear definitions but for an image containing an aircraft to be put into Airport, there needs to be particular aspects of interest, e.g. baggage trolleys, refuelling rigs, passenger buses, bridges, walkways, terminals, hangars, etc, or something of unique interest to the airport depicted.
Otherwise, assuming that the aircraft can be identified, the image should be placed in Aircraft.
Regarding the three you quote, I would agree that all should be placed in Aircraft but before transferring them, others may wish to comment.
Malcolm.