The European aviation system is a key enabler in guaranteeing economic welfare and is mandatory to ensure reliable mobility between large cities and metropolises. In 2014, aviation supported 8.8 million jobs in the European Union and contributed over {\texteuro}621 billion to European Union Gross Domestic Product, say 4.7{\%}. A predicted traffic increase of 1.9{\%} per year to reach 16.2 million flights by 2040, in combination with particularly saturated infrastructures, causes a significant challenge to maintain the system's functionality. This paper gives insights into the propagation of local performance improvements in the aviation network. Using a scenario with increased throughput at London Heathrow airport, changes in utilization and delay figures for the EUROCONTROL member state airspace are simulated using a macroscopic airport-airspace simulation model considering the 212 busiest European airports. The actual European airspace layout and equal-sized hexagon airspace portions are considered in this framework. Using a stochastic route generation model, flight trajectories are calculated, and a simulation of the air transportation network based on a flight plan containing over 35,000 flights is performed. The results indicate a significant impact on punctuality and throughput figures on a large part of the airspace in combination with a measurable traffic shift. A decrease in inbound delay can be observed for 2,252 flights (6.4{\%} of the network traffic volume). 39{\%} of them are taking off or landing at London Heathrow airport and benefit directly from the increase in performance. The remaining 61{\%} can be assigned to propagation effects since these affect only flights indirectly impacted by the performance improvement.