The simple way to make such delay is to start ignoring controls on jump, then after a wait or on Timer event - stop ignoring controls.
If you need something more complex, you can use "Is jumping", "Is falling", "Is (Not) on the floor" conditions, and control player's vector X and vector Y with actions.
TO get current flying direction and speed, use Player.Platform.VectorX and Player.Platform.VectorY expressions. To change it, use "Set vector X/Y" actions.
Also, don't forget to disable default controls for Platform behavior.