It will be very interesting to see how space travel will evolve throughout this century but do not forget that gravity dictates the motion of all objects in the Universe and the gravitational freefall orbit will always be the primary principle of getting from A to B in space. Space based propulsion systems can provide an important add-on to make space travel more economical and/or time saving.
"The future is not there waiting for us. We create it by the power of imagination”
Vilayat Inayat Khan