Other planes look small

[Ataros]

In real life you have about 180+ degrees field of view counting peripheral vision. Your monitor occupies only about 30 degrees out of 180.

Depending on FOV settings you are using in game you have 30, 60 or 90 degrees of ingame view squeezed into these 30 real-world degrees of your monitor. This fact makes objects smaller if you use 60 or 90 degrees FOV in game. To have a more or less real angular dimensions of Spitfire switch to 30 degrees FOV in game.