The 400A is a vast improvement from the original 400 in design and construction. Constructed of aerospace light alloys, it boasts an improved cabin space with fuel tank located under floor for more room to breathe. The seats turn 180 degrees allowing passengers full access while enjoying fully breathable air-conditioning on board; they also enjoy newly added amenities like cabin baggage area and refreshment cabinet which had been absent before! Newly relocated engine mounts make it less noisy inside this sleek modern jetliner as well as adding sound dampening material that ensures maximum relaxation during flight.