Charlotte Douglas International Airport has released details of a proposed lease agreement with major airlines that would help finance airport expansions, including an enlarged Concourse C and a tunnel connecting it to the main atrium. The airport says the agreement would generate $3 billion in airline rents and fees over the next decade. It would also give airlines a larger share of revenue from parking and concessions, while providing financial safeguards for the airport. Owned by the city of Charlotte, the airport operates without relying on city funding for its finances. Its revenue comes largely from airlines, federal passenger fees and parking. Airport officials say the lease would support continued growth over the coming decade. The proposed agreement sets terms for the airport and its major airline partners as Charlotte prepares for further expansion. The airport has identified the Concourse C work and connecting tunnel among the projects the agreement would help pay for.