Originally the stickers were "per aircraft" - I've changed that so a single sheet of stickers can be purchased for multiple aircraft, and they all point to the account instead of individual airframes.

That seemed fairer to me - no point in buying a sheet of 21 stickers for one aircraft when you only need a single sticker.

So stickers can be printed out (and stuck on via clear tape) or purchased pre-printed for unlimited aircraft now, provided a £2 monthly subscription is in place.