Straight lines are GREAT CIRCLE TRACKS on the VNC, not the VTA. Don’t forget to add or subtract magnetic variation from your straight line track on the VNC.

Projection Lamberts Conformal Conic Transverse Mercator
Scale 1 : 500 000 1 : 250 000
Rhumb Lines Curved toward equator Straight lines
Great Circles Straight lines Curved toward equator
Meridians Straight lines Straight lines