Kim and Khloe Kardashian are taking a girls' trip!

The Kardashian sisters boarded a jet Sunday afternoon to take off for the TV upfronts in New York, so it's more business than pleasure.

In fact, Kim had just returned from a trip with hubby Kanye West the day before. Kanye was said to be on a mountaintop in Wyoming, working on new music -- perhaps Kim went to visit him and they flew back together.

Now Kim's off again, sans Kanye ... can the two spend more than a few days together?!