Delta, Certares, Knighthead and Cox agreed to invest in Wheels Up, a provider of on-demand private aviation in the US. Financial terms were not disclosed. "Wheels Up is an integral part of Delta's portfolio of premium partners, and this deep relationship offers a significant opportunity to deliver compelling benefits to our customers that are unique in the travel space. This investment and new leadership puts Wheels Up on a strong path to future success," Dan Janki, Wheels Up Chairman and Delta Chief Financial Officer.