i not tried ar234's for a while now, because all bombers used to have flap bugs, but Ar234's NEED flaps to land, you cannot really do it without them. At least with the other bombers you can land without them with no issues at all...
one thing i have noticed is that bomber drones WILL NOT LAND with full flaps, so what i do is land with full flaps, then as soon as i touch down, retract the flaps fully and the drones drop down and land....