Decoration of my module would be based on post 2000. With an older aircraft I would expect the time frame can be viewed rather relaxed.

As it would be on a module with a width of 40 cm with the track in the middle, there is only 15 cm beyond the railway fence for scenery which is just a little over scale 20 m. Thats no place for a runway or winch so close to the railway. And I would rather tone it down than to put blinking lights and whirly thingies on it that could get on peoples nerves over time.

I found the site where I happened to see agricultural aircraft land and take-off as a child from a passing train. (one or two times for passing like 100 times). The runway is about 120m to 160m from the mainline. I see that this is now an aviation sport club. Maybe I go this route with half relief hangar back side and a small plane with a tarpaulin over the cockpit, rather like in the picture that i linked in my OP. This would leave more options for craft used.

Here is the site in ex. Eastern Germany that planted that memory:
https://www.google.de/maps/place/Beilrode/@51.5699364,13.0548739,533m/data=!3m1!1e3!4m5!3m4!1s0x47a7beb4e53b098b:0x900951e4efffe6ad!8m2!3d51.5710416!4d13.0669691

The only post 2000 agricultural aircraft that I know of available in n gauge is  this  https://www.shapeways.com/product/NQLCYMQJ5/crop-duster-spray-plane?optionId=61109949&li=marketplace , an alternative may be  https://images2.sw-cdn.net/product/picture/290x218_201483_192449_1479236005.jpg  or https://images1.sw-cdn.net/product/picture/290x218_21461344_12113332_1512909383.jpg

  You could have aircraft from any era, regardless of the era of your layout, by making your aviation cameo a 'film set'!

Lots of Star Wars filming was in the UK:

https://www.amazon.co.uk/Millennium-Falcon-force-awakening-Bandai/dp/B014VTPQ22

https://www.ebay.co.uk/itm/Japan-Bandai-1-144-Star-Wars-Millennium-Falcon-THE-LAST-JEDI-Plastic-Model/161874802233?_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D1%26asc%3D49130%26meid%3D15815ae4b9104927b24a4dcc260218a9%26pid%3D100011%26rk%3D1%26rkt%3D12%26sd%3D292285971423&_trksid=p2047675.c100011.m185

If you really want to show an agricultural aircraft then you could have a gliding field; gliding clubs often use ag. aircraft to tow gliders as they are highly powered so make very good tow aircraft.   You could show it by a fuel pump being refuelled.



Cheers Jon 

Seeing this thread reminded me of a photo I took whilst on holiday in New Zealand back in 2000.
I was a passenger in a Harvard on a pleasure flight and the pilot drew my attention to the crop spraying airstrip down below - which was situated on the ridge of a line of hills.



You can see the aircraft, airstrip and refuelling tanker on the photo above, as well as an admin building of some sort. The site was somewhere near Masterton, South Island, as the Harvard was based at the airfield in that town.

Good picture! That's NZ alright! 

Looking through the other picures, I appear to have a photo of the crop spraying aircraft at Masterton Airfield...



Presumably the hilltop strip is where it replenishes the spray tanks whilst spraying rather than returning to its base in Masterton.