They're extremely small, occupying a very small volume, to the point where something like wind resistance that we think about with accelerating large objects like planes becomes completely irrelevant. A rogue electron can fly straight through most solid objects through the "empty space" between atoms. Their mass is also extremely small, 9.1*10⁻³¹ kg, making them relatively easy to accelerate to near light speeds (in comparison to other forms of matter) as it takes very little energy to set them into motion. Particle accelerators accelerate electrons to 99% of the speed of light in the real world every day.
