In 2016 Gen David Goldfein, the Chief of Staff of the Air Force, called on the 9th Air Force (9 AF) to develop the capability to serve as a Joint Task Force Headquarters (JTF HQ), with the expectation that other numbered air forces would eventually develop similar capability. In August 2020, the 9 AF and 12th Air Force direct-reporting units and wings were integrated to form the 15th Air Force (15 AF), which now continues to carry out the mandate to develop a JTF HQ capability. In this report, the authors examine the U.S. Air Force's (USAF's) efforts to develop a joint task force capability that maximizes airpower's contribution to joint warfighting-one that has the organization, training, and equipment required to effectively carry out a JTF HQ mission when called on to do so. The authors conducted literature reviews, engaged in discussions with subject-matter experts, attended staff exercises, and generated case studies of operations. They also examined a data set of 88 JTF HQs activated between 1990 and 2017 to gain insight into the causes and conditions that typically result in JTF HQ formation and to understand the factors that shape JTF HQ mission sets, selection processes, and their duration. The authors' findings and recommendations reflect research conducted prior to 9 AF's integration into the new 15 AF, but they remain relevant to 15 AF personnel and others interested in understanding the challenges and opportunities associated with USAF efforts to stand up a JTF HQ.