In one of the Kelly Johnson biographies that I've read, it's recounted that Johnson rode along on a "test flight" of a Constellation that Hughes insisted on making, with Lockheed's chief test pilot in the right seat. Basically a series of patterns and touch-and-goes. After not too many of them, Johnson ordered Hughes and the company pilot to switch seats, and to take him home. Hughes never forgave Kelly for the insult, and Kelly vowed to never again fly in an airplane being piloted by Hughes. Hard to imagine Hughes single-piloting a 1649, particularly, for a week,but who knows?