Should an Aviation include Crème de Violette? The "Aviation" cocktail is an IBA "official" cocktail. It is listed on the IBA website with these ingredients and instructions:


  All Day Cocktail
  
  
  4.5 cl Gin
  1.5 cl Maraschino
  1.5 cl Fresh lemon juice
  
  
  Shake and strain into a chilled cocktail glass.


To my surprise this doesn't list Crème de Violette at all: not in the ingredients, and not as e.g. "a dash" in the instructions.

Nearly all recipes I've seen so far though (e.g. How to Drink) do have Violette, and they all call out the Aviation as a "blue as the sky" cocktail because of that creme.

So what's the deal here? Is the IBA website just lacking it (perhaps because it's not a "core" ingredient but just a dash or a barspoon, usually)? Or is the "official" version actually without it?
According to wikipedia, the original Hugo Ensslin's recipe calls for 2 dashes of crème de violette.

In the same article there can be some variation on the theme, with or without crème de violette.

The Gin foundry website offers 2 recipes, with or without it; the version without the crème de violette dates from the 1930s and they say it might be because the product was hard to found at that time (ww2 era)

I'd say, if you want to be fully original, use the proper recipe with the crème de violette, but if you cannot find it, then it is not that big a deal as it is still historically correct.