Better to know the model you are using, if only to understand its limitations, than to kid yourself you have moved to a deeper, model-free plane.

ECONOMIST: Knowing your place

This is a special type of Earth model which traces its idealised "horizontal" surface - the plane on which, at any point, the pull of gravity is perpendicular to it.

BBC: Europe's Goce satellite probes Earth's gravity

"I am wary of a plane model that has fire problems and leaks fuel, " said Atlanta-based businessman Bobby Burns, a project manager who takes more than 50 trips a year.

CNN: STORY HIGHLIGHTS

In another model being pushed by incumbents in the in-flight entertainment business, airlines install a plane-wide content-streaming system with an array of movies, TV shows, games and other content, generally alongside broader Internet access.

WSJ: Some Airlines Lend iPads for In-Flight Entertainment Systems