Kim Kardashian and Kanye West -- Quick Pit Stop for Well-Traveled Fetus

Kanye West and Kim Kardashian were all over each other -- like a couple o' teenagers -- when they touched down in LA this morning ... just hours after announcing they've got one in the oven.

KK & KW were arm in arm -- a few paces behind proud momager Kris Jenner -- as they strolled through LAX ... but it won't be long before the couple and their little (very little) one are back in the air.

As TMZ first reported ... Kim's going through with her scheduled NYE appearance tonight at 1 Oak Nightclub in Las Vegas.