This airliner is able to take off and land from any field of sufficient size with no runway. A hard area will be needed for the weight of the aircraft.
The fan engines provide vertical lift and some manoeuvrability during take off and landing and the forward thrust engines are powered up after sufficient height is reached. When flying speed is reached the fan engines may be switched off and the slots where the fan engine air flow passes above and below are closed to form a smooth slipstream. The fuel tanks are on pods adjacent to the forward propulsion engines to enable ejection in the event of an accident.
The wings are of normal design for a subsonic airliner and the controls are normal.
The twin elevator and rudder support extends fro the box fuselage to the single elevator and tail plane and rudder and fin.
The fuselage is a box where the 400 hundred passengers sit in separated division for safety and comfort. The passengers are able to walk around for socialising and refreshments.
This area has no portholes and no view ports and is strengthened to enable it to survive impact in order to increase the survivorship of passengers in an accident.
I suggest the seating is for family groups or for business groups.
The aircrew's compartment is spacious and has big viewports of optical flat glass to enable maximum visibility. The navigation equipment should include collision avoidance radar, PPI radar (H2S) and GPS.
The collision avoidance radar must be able to identify other aircraft from transponders and the radar should include radar altimeter for control of height so landing can be carried out without ground control.
This means the pilot needs a view of the terrain immediately below.
The tubes that support the tail plane elevator are big enough for an aircrew to crawl down for emergency repairs and to inspect the fin and tail plane and contains the control pipes. The hydraulic pips should be flexible hoses to reduce the risk of fracture and also electric cables housed here. These control units should be duplicated in each tube to make redundancy.