There's a bug with the drag. Even If the cheat "no drag" is off, when you launch a rocket and it spawns on the launchpad, drag will be originally disabled. To activate it, you need to open the menu, hit Exit, and then from the main menu (the one with the "Spaceflight Simulator" logo) hit Resume Game.
That will enable the real drag. Otherwise you'll launch without drag, which is kinda cheaty.