I expect the AEG to be expensive and I just put it down to all WnW kits being limited run items. The lower the production numbers, the more expensive they are. We pay a premium because there just isn't the same interest in WWI aviation modelling as there is in other genres of the hobby.
It's interesting to compare it to the 1:35 AFV Club Matador gun tractor I'm currently building, as the part count is in the same ballpark. The Matador consists of 496 parts in plastic, 28 clear parts, 38 PE parts, 5 vinyl tires, 1 decal sheet, and 1 sheet of clear film windows. This comes with a $53.00 price tag, depending on where you buy it.
Cheers,
Chris