Ah - rather an idealised great circle example...

Below is BA 285 LHR-SFO on 9th Dec - the first mapping is an equal area, the second a Mercator....



Things to note that all equal area projections aren't really equal area (!), and while Mercator is often used, it's terrible at representing the higher latitudes!

BTW - you'll probably notice (or find out) that for TATL flights westbound tend to be on more northerly routings to avoid the (headwinds of the) jet stream, while the eastbound services tend to be further south take advantage of the jet stream (tailwinds).