Reconheço que essa expressão sempre tem me resultado muito HILARIA na língua Portuguesa. E é muito comum que os alunos de Inglês perguntem como falar essa expressão na língua de Shakespeare.
Bom, primeiro vamos em Português. A forma mais fácil de utilizar essa gíria tão "brasileira" é:
TO DAYDREAM or also YOU'RE IN LALA LAND
Examples:
Stop daydreaming and do what I'm telling you. - Pare de viajar na maionese e faça o que estou te falando.
I think you're daydreaming. - Acho que você está viajando na maionese.
Ohh Gosh, you're in LALA land. - Você está viajando na maionese.
Agora em Inglês - Intermediate Level
"Viajar na maionese" is an idiom (expressão idiomática) and usually there isn't a literal translation for idioms, because they reflect culture and contexts that sometimes can't be found in others languages/countries.
Therefore, we better look at the "meaning" of the idiom; the context where it's being used, rather than the literal translation. Here is the equivalent meaning of "viajando na maionese" :
You are 'spaced out'. Come back to earth!
I was totally 'out there'. I didn't pay attention to one word of what he said.
She is 'daydreaming'! (said with certain irony) Of course she is not going with us!
You are 'zoned out'. Don't be silly!
You are 'in la la land'. Be realistic!
Obs.: I have also seen these different spellings: Lala Land; La La Land; Lalaland. Go figure! I guess it doesn't matter when you are in lalaland anyway, does it? ;-)
These are a few ways to express that someone is not quite there, is lost in space (figuratively), or something like that.
