Purpose – Assessment of the Direct Operating Costs (DOC) and fuel consumption of the Airbus A321LR using typical use-cases and comparison with those from similar aircraft. Investigation of the flexibility of the cabin layout using examples from different airlines. Calculation of Ecolabels based on different cabin configurations. --- Methodology – All aircraft-related data is retrieved from the Original Equipment Manufacturers' (OEM) manuals. The DOC assessment uses the Association of European Airlines (AEA) and the TU Berlin method. The fuel consumption is assessed with a tool based on the Breguet Range equation, using successive iterations. The Ecolabel considers resource depletion, global warming, local air quality, and noise pollution, weighted and combined into one overall rating. A cabin study contrast layouts from Airbus with those from operators and also considering ergonomics. --- Findings – The A321LR offers improvements in flight range compared to A321CEO and A321NEO. It can operate medium range very efficiently with only minor payload reduction. Very low-density layouts of a few airlines are purely their marketing preferences. Costs per seat and Ecolabel rating vary significantly between low-density and high-density cabin configurations. Predictions for the A321XLR are also very favorable. --- Research Limitations – DOC results are not unique numbers but depend on the DOC method applied. Some of the characteristics for the XLR can so far only be estimated, since its entry into service is scheduled for 2023 and, as such, after the submission of this thesis. --- Practical Implications – Good reasons for operating the A321LR are elaborated. The Ecolabel allows passengers and operators to openly discuss the ecological implications of different cabin layouts. --- Originality – This seems to be the first scientific report that extensively investigates economic and ecologic aspects when operating the A321LR with different cabin layouts.