can you download netflix shows on a mac for a flight?

Check each show has the download icon before you rely on it, not every title can be downloaded. Some downloads also expire a while after you first press play, so don't start an episode the week before and expect it to still be there on the plane.

Not on the Mac itself, unfortunately. There's no Netflix app for macOS and the browser version doesn't do downloads. Even on Apple Silicon Macs the iPad app isn't offered. What works is downloading on an iPhone or iPad (or an Android tablet) before you leave. Do it on wifi at home, not at the gate, and open the app once while you're still online so the downloads don't get flagged as expired. Some titles also have a limit on how many times you can download them, so don't go deleting and redownloading the night before.