Check out these photos/video, obtained by TMZ, showing J Lo's mode of transportation over in Europe ... and no, this ain't a private jet -- it's a regular old airplane full of a bunch of normies, on which she flew Saturday going from Naples to Paris.

The singer/actress was in the cabin with everyone else, and had a bodyguard sitting next to her ... taking up aisle duty while she occupied the window seat, minding her business.

As you can see ... she didn't seem to be getting bothered much -- still ... she was kinda packed in like a sardine ... and even before the flight, she was spotted in the terminal along with everyone else, going through the motions of customs, etc. Like we said, relatable.

Of course, J Lo popped up in Italy just last week for a solo trip without Ben ... getting some R&R with friends along the beautiful Positano coast, where she was beaming.

While J Lo wined and dined in Italy and flew to France for Paris Fashion Week, Ben's been in L.A. ... where he's spending time with his son and hitting the marital home. Of course, he ran into a little drama there with paps ... but the bigger point is, he and Jen are apart.

As you know ... Ben and Jen appear to be hurtling towards divorce, and are living separately as they quietly try to unload the $60 million Beverly Hills home they purchased together just last year.

We've seen Jen and Ben hang out together here and there over the past several weeks -- mostly for family events -- but on this occasion ... it looks like she needs some me-time.

A Euro flight up in the air is the perfect place for that ... just a superstar and her thoughts.