Almost a dozen Am Law 100 firms have landed lead advisory roles on the proposed $11 billion merger of American Airlines parent AMR and US Airways Group—a Valentine’s Day deal that could create the world’s largest airline.

Thursday’s announcement that the two companies have agreed to merge follows months of negotiations that began when US Airways started circling its insolvent rival last year. Should the deal secure the required regulatory, shareholder, and creditor approvals, it would cap more than a decade of consolidation in the U.S. commercial aviation industry.