On or before June 30, 2008, the San Diego County Regional Airport Authority and the consolidated agency shall enter into an agreement for the coordination of responsibilities for the adoption of, and updates to, the regional aviation strategic plan and the airport multimodal accessibility plan for San Diego County pursuant to this article. The agreement shall include provisions for coordination and timing of the preparation and maintenance of the plans. The agreement shall also provide for coordination of efforts to obtain funding from outside sources and equitable allocation of funding responsibilities for the airport multimodal accessibility plan.