I was flying from San Jose to Denver. The plane looked like an ordinary 737. But after we were airborne, and the pilot turned off the seatbelt sign, the plane expanded quite a bit. There were multiple restaurants, a library, a garden with a fountain, and all kinds of neat stuff.
However, the flight was very scary. Instead of flying at a normal altitude (perhaps 35000 MSL), the pilot was hugging the ground within a few hundred feet, and sometimes closer. That wouldn’t be so bad in flat areas, most of the terrain between San Jose and Denver is mountainous.