no that wouldnt make any sense, if you had w on one axis and s on a different then that would be like having w move forward and s move right. what you should do is to make a input axis event in the project settings ->engine->input. make an axis input event and have w as a value of 1 and s have a value of -1 (if your in the third person example this should already exist). you can do the same thing for your altitude adjustment for flying too.
it has also just occurred to me that when you mentioned axis you may have been referring to my second picture above, in the picture the thumbstick x axis event is for strafing left and right (direction based on right vector). the y axis event was the one for forward and backward movement. the event with the comment turn on it is for turning / rotating the character.
