Kanye West and Bianca Censori Jet Off to Japan, Fly Commercial

Kanye West and Bianca Censori are passing on the fabulous life -- at least for one day -- as they jumped on a commercial flight heading to Japan, and someone spotted them snuggled up in economy seats!!!

The surprised passenger snapped a quick TikTok of the couple seated in a bulkhead row ... Ye was out stone cold while wearing a bathrobe with "Ye" embroidered on the chest -- just in case the coach commoners didn't recognize him.

Bianca was scrolling through her phone in the same flowy gown she traveled in at the beginning of what appeared to be a trip to celebrate Kanye's 47th birthday.

As we reported, the couple dined at the renowned Il Palagio restaurant in Florence, Italy for 2 hours last week -- and the "Vultures" rapper caught up on his phone scrolling at the table.

They're currently in Japan where we're sure more adventure, and/or risque behavior, awaits!!!