Continuity mistake: While in the shuttle bay, Dr Finn and her family are preparing shuttle ECV-197-2. During the rest of the show they are flying shuttle ECV-197-1. (00:01:15 - 00:05:20)
About a Girl - S1-E3
Visible crew/equipment: Right after the opening credits, when Dr. Finn tells Bortus, "I will not perform a sex change on a perfectly healthy newborn," the camera pans to the left as she walks to her desk, and the yellow T-mark can be seen on the floor in her office, where Bortus will stand. (00:03:25)
Continuity mistake: As Seth MacFarlane tells the crew to take things seriously, he's got his hands held parallel to each other. The shot changes and his fingers are interlocked.
Continuity mistake: When the crew is working to disable the device helping Pria to hijack the Orville, the Chief drills a hole and creates a great deal of metal/material shavings on the top of the device, which disappear. The device is also aligned differently in respect to the components of the Orville's circuits from the Chief's drilling shot to Isaac's probing shot. (00:34:21)
Answer: The book "Flatland", which is mentioned in the show, is a real book that may answer your questions in full (it's the story of a 3-D being experiencing the 2-D world and the 1-D world). In the 2-D world, there is no height, so there's no way to slice anything in half (horizontally). A being living in the 2-D world sees any object or being as a line (it's messy, but the lines have thickness, just not height, but all thickness is the same). So if the Orville was seen, it would only be seen 2 dimensionally and be seen as a line and others beings could just move out of the way. While there were buildings in "Flatland", perhaps this world doesn't have any, or the Orville didn't bump into any. There is death in "Flatland" when a being isn't careful and is poked, but these are usually by lines and triangles and the Orville would more like the circles and not in danger of poking anything.
Bishop73