The Royal Air Force, second to none. Generally considered as second to the USAF due to having less planes, but as they say: it's not how big it is, it's how you use it!
Of course, being able to determine the difference between allies and enemies is always an asset that the RAF have had, whereas certain other Air Forces consider anything on the ground to be fair game.
"Bally Jerry, pranged his kite right in the how's-your-father. Hairy blighter, dicky-birded, feathered back on his Sammy, took a waspy, flipped over on his Betty Harper's and caught his can in the Bertie!"
"I'm afraid I don't quite follow you, Squadron Leader!"
(The RAF don't actually talk like that... all the time)