WASHINGTON, May 23 -- Law firms assisted companies in the following recently announced transactions: * * * Debevoise & Plimpton also advised American Airlines and American Airlines Group in a $400 million special facility bond offering issued by the Tulsa Municipal Airport Trust. The team was led by capital markets partner Paul Rodel and finance counsel Michael P. McGuigan, with finance partner Brian Liu and capital markets associates Justin Norris and Amy Pereira. Debevoise & Plimpton LLP ad more ST