Currently, it is not possible to configure VTOL aircraft to point the nozzles down to allow for proper vertical take-off. As soon as you go above 5kph you can turn the nozzles towards ground (that is with using "vtol = 1" or "vtol = 2").
On the other hand using "vtol = 3" or "vtol = 4" causes the opposite, they will point to the ground until you reach above 5m altitude when you can point them backwards. However VTOL aircraft like F-35 should allow both at any time.
Getting "vtol = 5" that has no restrictions whatsoever would be the best solution to this.