Aviation Integrated Model (AIM)

The Aviation Integrated Model (AIM) is a unique integrated assessment tool of the global air transportation system.

Originally funded by EPSRC and NERC, AIM enables the analysis of policies to reduce the environmental impact of air transportation.  It consists of seven interacting modules, each covering a different component of the air transport and environment system.  Four of these modules generate a three-dimensional emissions distribution due to air traffic, worldwide:

  • Air Transportation Demand Module: simulates the true origin-ultimate destination passenger air trips between more than 1,000 airport pairs worldwide.
  • Technology and Cost Module: specifies the techno-economic characteristics of current and projected future aircraft designs for different aircraft size classes.
  • Fleet planning model: assesses the adoption of different aircraft designs in the global aircraft fleet and the optimum use of each design on specific routes.
  • Airport Activity Module: forecasts the global aircraft traffic required to satisfy the demand projected by the Air Transport Demand Module and estimates the resulting ground delay given the airport capacity constraints within the worldwide network.

The air traffic by flight segment generated by the Airport Activity Module is the main input to the Aircraft Movement Module, which works in conjunction with the Aircraft Technology and Cost Module to identify the amount and location of emissions released from the required flight segments, accounting for inefficiencies introduced by the air traffic control system.  These four modules are run iteratively to find an equilibrium solution for aviation system demand, the supply of aircraft by route and technology characteristics for the given year, scenario and policy variables.

The other three modules consist of environmental and economic assessment tools.  The chosen architecture permits important feedback and data flows between the key system elements to be captured and provides natural input sites for policy measures and airline and passenger responses to be imposed upon the system.

Model summary

Type:Integrated Assessment Model
Purpose:Estimate the various impacts of policies that aim at mitigating the environmental impact of global air traffic
Spatial scale:1 degree x 1 degree x 1 km altitude
Temporal scale:Annual, with airport congestion on 4-hour intervals 
Main contact:Andreas Schäfer
Other contacts:Antony EvansLynnette Dray (Cambridge)



More information about the model is available at the AIM website.



Journal papers

1. Evans A. (2014) Comparing the impact of Future Airline Network Change on Emissions in India and the United States, Transportation Research Part D, 32: 373-386.

2. Schäfer A., Waitz I.A. (2014) Air Transportation and the Environment, Transport Policy, 34: 1-4.

3. Evans A., Schäfer A. (2014) Simulating Airline Operational Responses to Airport Capacity Constraints, Transport Policy, 34: 5-13.

4. Dray L., (2014) Time Constants in Aviation Infrastructure, Transport Policy, 34: 29-35.

5. Dray L., Evans A., Reynolds T.G., Schäfer A., Vera-Morales M., Bosbach W. (2014) Airline fleet replacement funded by a carbon tax: an integrated assessment, Transport Policy, 34: 75-84.

6. Krammer P., Dray L., Köhler M. (2013) Climate-neutrality versus carbon-neutrality for aviation biofuel policy, Transportation Research Part D, 23: 64-72.

7. Evans A., Schäfer A. (2013) The Rebound Effect in the Aviation Sector, Energy Economics, 6: 158-165.

8. Dray L. (2013) An analysis of the impact of aircraft lifecycles on aviation emissions mitigation policies, Journal of Air Transport Management, 28: 62-69.

9. Dray L., Schäfer A., Ben-Akiva M. (2012) Technology Limits to Reducing Transport Sector Greenhouse Gas Emissions, Environmental Science and Technology, 46(9): 4734-4741.

10. A. Evans & A. Schäfer (2011) The Impact of Airport Capacity Constraints on Future Growth in the US Air Transportation System, Journal of Air Transport Management, 17: 288-295.

11. Dray L., Evans A., Reynolds T.G., Schäfer A. (2010) Mitigating Aviation Carbon Dioxide Emissions: An Analysis for Europe, Transportation Research Record, 2177: 17-26. 

See the AIM website publications page for a full list of AIM-related publications, including reports, conference papers and PhD theses.