Harry Craddock's 1930 "Savoy Cocktail Book" lists the recipe as two-thirds dry gin, one-third lemon juice, and two dashes of Maraschino liqueur, leaving out the Creme de Violette completely. This is the cocktail you will likely receive in most bars because, until Rothman and Winter came out with their version in 2007, Crème de Violette was no longer in existence. It is still difficult to find (though can be found online at BevMo and other web retailers), but frankly, this recipe is not an Aviation, lacking both the floral notes of the violet flavor and distinctive blue color and should not be called such. It's understandable that most bars won't stock Crème de Violette as it is not used in that many cocktails but if they don't an Aviation should not be on their drinks menu.
Crème Yvette is sometimes substituted in versions that call for Crème de Violette but it's not a true violet liqueur as it uses a combination of berries and orange peel with the violet. As a result, I find this liqueur too fruity, too heavy and the violet notes too faint for the original intentions of the Aviation. Besides, it's upwards of $50 per bottle! If I were to pick any substitution at all it would be to use the essence of another floral element, adding in a drop or two of hibiscus essence or even B'lure, though both would fly away from the wild blue yonder color of the original drink, the hibiscus turning the drink a distinct pink color and the B'lure changing from blue to fuchsia as it interacts with the lemon juice. So, not an Aviation either!
If you want to stick as close as possible to the original Aviation, then buy yourself a bottle of Rothman and Winters Crème de Violette, Luxardo Maraschino Liqueur and some good dry gin!
2 Oz. Aviation Gin (come on, you have to, it's called Aviation!)
1/4 Oz. Maraschino Liqueur (Luxardo Recommended)
1/2 Oz. Fresh Lemon Juice
1/4 Oz. Crème de Violette
TOOLS: Cocktail (Martini) glass, Cocktail shaker, Hawthorn Strainer
GARNISHES: Lemon Twist, Homemade (or Luxardo) Maraschino Cherry
Chill your glass in the freezer.
Add the gin, Maraschino liqueur, lemon juice and Crème de Violette to an ice filled cocktail shaker and shake until well chilled.
Strain into your chilled glass. Garnish with a lemon twist and a Maraschino cherry.
Like Raymond Reddington (James Spader in NBC'sThe Blacklist) says in The Freelancer episode, "It's from the '20s, tastes like spring, doesn't it?"
BLUE MOON - Leave out the Maraschino liqueur.
MOONLIGHT - Replace the Maraschino liqueur with Cointreau.