Shortly after the opening of Suvarnbhumi Airport, officials decided that Don Mueang would still need to handle domestic commercial flights due to faster-than-projected air traffic growth throughout Asia. Airports of Thailand Public Company Ltd. (AOT) determined that using the existing facilities at Don Mueang would increase the flexibility needed to handle the growing air traffic demands before Suvarnabhumi Airport could be expanded.
On behalf of AOT, the International Civil Aviation Organization contracted WSP to prepare a traffic allocation strategy for the two airports and a plan for their future development. WSP prepared a revised master plan that included:
- A status review.
- Inspection and appraisal of airside and landside facilities at both airports.
- Passenger surveys.
- A strategic plan for air traffic allocation.
- Comprehensive airport planning and design parameters.
- Landside and airspace capacity analysis and planning, including simulations.
- A land-use and facility plan.
- An environmental impact study.
- Alternatives for airport development, including financial assessments (capital and operational expenditures).