Why would France build Joffre at home?

Why would France not order an aircraft carrier from the United States to accelerate its response?

Because France would prefer to fund its own yards, expected time to build domestically, and faced political and economic barriers to sending a major naval contract abroad.

France regards the ability to design and build its own major warships as part of being an independent naval power. Ordering escort carriers from the United States in a later emergency is different from sending a prewar fleet-carrier program abroad. French legislators would also find it harder to approve a large contract that exports money rather than supporting domestic yards and employment. Severe demographic and economic damage from the First World War already makes interwar naval funding difficult. Advancing Joffre at home is therefore more plausible than buying an American substitute.