I don't know about the cat's pajamas, but I do know about the bee's knees. Actually both expressions are popular lingo from the 1920s, with a similar meaning of some person or thing that is special or awesome, to use more up to date slang.
The bees' knees is also the name of a classic cocktail with other names like the Bumble Bee. It's easy to make - and it's my first choice for a cocktail to welcome spring. Think of a Tom Collins but with organic honey as a natural sweetener instead of sugar. Better yet with local honey!
Fill an old-fashioned glass with crushed ice and add the honey and lemon juice. Stir and slowly add the gin. Garnish with a rosemary sprig and/or lemon slice or peel.
*Combine equal amounts of honey and water in a saucepan and simmer over low heat until reduced by half.
During prohibition, many cocktails like this one came into being because the honey and lemon were easy ways to disguise the flavor of bathtub gin!