The atmosphere has absorption bands near 20 and 60 GHz. Sufficient electromagnetic energy at these frequencies could ionize surrounding air. Electrostatics could then be used to move the air, which could also generate a reactive force on the craft. The craft would tend to be surrounded by a corona. This method of propulsion would suffer from a major drawback: it would not work outside the atmosphere.
It may be possible to propel a vehicle using electromagnetics alone, even in a vacuum. Although photons travel at c, using the principle of zero time, the craft could be propelled by reactive forces regardless of distance from objects. Since matter tends to be paramagnetic, exhibiting a slight reinforcing reaction to imposed magnetic fields, phase controlled fields could be used to generate force. The drawbacks of this method are that very intense fields would be required and, for interstellar travel, the light barrier would still be an obstacle.
While directing nuclear energy, electrons will be displaced from adjacent atoms. This is likely to yield corona effects due to the high energy levels. Because a craft is likely to have metallic paths, loops, energetic electrons will also cause currents to flow, leading to electromagnetic effects. These electromagnetic effects are likely to be a by-product of craft operation and are probably not the principle method of propulsion.