Due to strong demand for air travel before the COVID-19 pandemic, major airports were constrained in capacity and this issue was expected to worsen in the coming decades. Novel aircraft (concepts) could help to alleviate these capacity constraints. However, the market competitiveness and impact of novel aircraft is often challenging to assess, especially in the preliminary design phase. This research aims to construct an aircraft market demand model which uses basic aircraft design parameters and expected future air travel demand as input for a fleet allocation problem with flexible passenger allocation. In this competitive environment, novel aircraft designs compete with existing aircraft for market share in both the current and future aviation landscapes. The novel PrandtlPlane developed by the ParsifalProject, designed with the purpose of alleviating capacity-constrained airports, serves as a case study. Results show that the PrandtlPlane offers strong competition to in-service narrowbody and widebody aircraft with further opportunities for a long-range version.