Dawn Hawk

When Focus's great-aunt Petronel dies, aged 86, Bryce and Focus have the beginning and the end of a poem as the only clues to long-forgotten mystery.
After the Wright Brothers immortalised themselves at Kitty Hawk, they went on to make commerical aircraft. The first two were 'floatplanes', called Hawks, and at least one was sold in New Zealand and later disappeared from official records.
Had Petronel discovered the Hawk? Was she restoring it? And what happened to the money from the American Army payroll robbery?