The flyer jumps straight up. You will need a very slow and soft tempo for that jump. count two seconds for going down and one second for going up (the actual jump). Be soft in the turning point of the tempo.
That will make it possible for the base to follow the flyers tempo. In the moment when the flyer leaves the elbows of the base, the base can follow and help by pushing out from the shoulders/scapular. Catch the flyer and stabilize the position.
Try first with spotting and reevaluate after each try (to much in front, to fast, the tempo is to hard...)