The MBA 13 and MBP 14 have very similar working real estate on their displays. See their default scaled resolutions for better understanding.
The MBA 15 and MBP 16 have very similar working real estate on their displays. Again, see their default scaled resolutions for better understanding.
If someone is okay with a smaller working real estate on their display, they should consider a MBA 13 or MBP 14. If they want or need MORE working real estate, they shoud consider a MBA 15 or MBP 16.
It's a pet-peeve of mine when people look at the price of the MBA 15 and recommend that someone get the MBP 14 instead. They are very different experiences and some people won't be happy with the smaller working space