FAA’s primary mission is to provide the safest, most efficient aerospace system in the world. FAA oversees operating and maintaining this system, known as the NAS, as well as the safety of aircraft and operators. FAA operates and maintains the NAS through the following: a workforce of technicians, air traffic controllers, and other staff who work in airport towers, terminal areas, en-route centers, oceanic air traffic control centers, and other facilities, and the ATC and other supporting systems and infrastructure, including ground-based surveillance radar facilities, communication equipment, automation systems, and the facilities that house and support these systems. Various offices within FAA are responsible for the air traffic control system and its modernization through the NextGen initiative. The ATO, headed by the COO, is responsible for the day-to-day operations and maintenance of the air traffic control system. The NextGen Office, ATO, and Office of Aviation Safety are involved with various aspects of NextGen’s management and implementation. The Office of Airports is responsible for all programs related to airport safety and inspections, standards for airport design, construction, and operation. In this role, the Office of Airports supports the implementation of NextGen. These offices report to the Deputy Administrator, who also has the designation Chief NextGen Officer (see fig. 1). FAA receives funds annually through congressional appropriations into four accounts: The operations account funds, among other things, the operation and maintenance of the air traffic control system. The facilities and equipment account funds technological improvements to the air traffic control system, including NextGen. The research, engineering, and development account funds research on issues related to aviation safety and NextGen systems. The Airport Improvement Program account provides grants for airport planning and development. See figure 2 for percentage of fiscal year 2013 congressional appropriations by account. Congress appropriates funding from the Airport and Airway Trust Fund, which receives revenues from a series of excise taxes paid by users of the national airspace system, as well as from general revenues. The Trust Fund provides nearly all of the funding for FAA’s capital investments in the airport and airway system. Revenue sources for the trust fund include passenger ticket taxes, segment taxes, air cargo taxes, and taxes paid by both commercial and general aviation aircraft. The trust fund also provides a substantial portion of funding for operations—for example 80 percent of FAA’s $15.9-billion funding in fiscal year 2014. The remaining amount was appropriated from general revenues. Whereas FAA operates, maintains, and regulates the air traffic control system in the United States, in countries such as the United Kingdom, Germany, and Canada, their air navigation service providers (ANSP) are commercialized and handle the day-to-day operations of the air traffic control systems, while the governments regulate these activities. These ANSPs employ the workforce, maintain the infrastructure, and undertake modernization efforts. International ANSPs vary in the extent of government ownership and commercialization, with some as state-owned corporations, some as public-private partnerships, and some as private corporations. According to two recent international analyses comparing ANSPs from different countries on a range of performance measures including productivity, efficiency, and cost-effectiveness, FAA operates one of the most efficient ATC systems. According to a 2012 comparison of air traffic management performance between FAA and the combined 37 ANSPs of Europe, the United States had a similar arrival punctuality rate with Europe for a similar amount of continental airspace. Another international comparison, completed in 2013, of performance data from FAA and 22 global ANSPs showed similar results, with FAA ranking second in productivity. However, it is difficult to compare performance, as air spaces are different. For example, FAA’s ATC system controls about 60 percent more flights than Europe, its airspace is nearly twice as dense as that of the European ANSPs, and it has 23 percent fewer air traffic controllers. In addition, Europe has to coordinate among 37 ANSPs, while the United States has one. Although FAA is recognized for safety and relative efficiency, its attempts to modernize the ATC system have been less successful. We have chronicled the difficulties FAA has faced completing what it envisioned initially in 1981 as a 10-year program to upgrade and replace NAS facilities and equipment. For example, in August 1995, we found substantial cost and schedule overruns. To address these difficulties, in the past, Congress gave FAA acquisition and human capital flexibilities to improve the agency’s management of the modernization program. Specifically, in 1995, Congress directed FAA to implement new acquisition and personnel management systems and exempted the agency from certain federal acquisition and personnel laws and rules. In June 2005, we found that FAA had largely implemented these flexibilities. However, modernization difficulties persisted, and Congress directed FAA in 2003 to conceptualize and plan NextGen. NextGen was envisioned at that time as a major redesign of the air transportation system to increase efficiency, enhance safety, and reduce flight delays. NextGen is planned to incorporate precision satellite navigation and surveillance; digital, networked communications; an integrated weather system; and more. This complex undertaking requires acquiring new integrated air traffic control systems; developing new flight procedures, standards, and regulations; and creating and maintaining new supporting infrastructure. This transformation is designed to dramatically change the roles and responsibilities of both air traffic controllers and pilots and change the way they interface with their systems. The involvement of airlines and other aviation stakeholders is also critical, since full implementation of NextGen will necessitate airlines and others to invest in new avionics and other technologies to take advantage of NextGen technologies. See figure 3 for the expected benefits from NextGen implementation as depicted through improvements to the phases of flight. In addition, to address stakeholder and congressional concerns over NextGen management practices and the pace of modernization efforts over the last decade, FAA has reorganized several times. These changes included: In 2003, FAA hired a COO and in 2004 created the ATO to transform the air traffic control system into a more performance- based organization and improve the modernization effort. In 2011, FAA moved the office responsible for coordinating NextGen activities—the NextGen Office—out of the ATO and made it report directly to the Deputy Administrator to increase NextGen’s visibility within and outside of the agency and create a direct line of authority for NextGen. In 2012, FAA created the Program Management Office (PMO), within the ATO, to improve the oversight of ATO’s acquisition and implementation efforts, including those for NextGen. At the direction of the FAA Modernization and Reform Act of 2012, FAA created the Chief NextGen Officer position, currently held by the Deputy FAA Administrator, who reports directly to the FAA Administrator. However, challenges continue to persist, as we found in April 2013, August 2013, and February 2014. Specifically, we found that while FAA had made some progress in implementing the NextGen modernization program, FAA continued to experience challenges, including in the following areas: Human capital activities: Improving and sustaining NextGen leadership and preparing FAA’s workforce. Program management: Prioritizing projects to achieve some near-and mid-term benefits and managing NextGen interdependencies. Coordination with industry stakeholders: Gaining greater involvement from industry stakeholders in FAA’s initiatives and equipping aircraft with NextGen technologies. Transitioning to NextGen: Balancing the needs of the current ATC system and NextGen and consolidating and realigning FAA’s facilities. In these reports, we made six recommendations to FAA regarding the improvement of budget planning, performance-based navigation implementation, and stakeholder coordination and communication. DOT concurred with these recommendations, but as of August 2014, had not yet implemented them. Stakeholders’ views on FAA’s capability to operate an efficient ATC system generally align with the two international analyses described previously. Almost three-quarters (53) of the 72 stakeholders who provided a rating rated FAA as moderately to very able to operate an efficient ATC system. Four stakeholders did not rate FAA on this issue. (See table 1 for the stakeholders’ ratings.) In addition, during our interviews, over three times as many of the stakeholders specifically mentioned that the ATC system is generally efficient (37) than those who said the system is not (12). Fourteen stakeholders specifically said that FAA operates the most efficient system in the world. Notwithstanding this generally positive assessment, stakeholders raised areas where FAA could improve. For example, 29 stakeholders indicated that FAA does not handle irregular air traffic operations very well, such as those caused by inclement weather. Stakeholders’ views regarding NextGen implementation also reflect our past findings on FAA’s difficulties in implementing the initiative. Eighty percent (56) of the 70 stakeholders who provided a rating rated FAA as marginally to moderately able to implement NextGen. Six stakeholders did not rate FAA. (See table 1.) In addition, during our interviews, more than three times as many of the stakeholders (43) said that FAA’s overall implementation of NextGen was not going well than those who said it was going well (13), and 30 specifically mentioned that FAA was not doing well managing technology programs in general and NextGen acquisitions and contracts in particular. In our interviews with FAA senior management, officials acknowledged that stakeholders’ complaints about NextGen were not new. They also said that the agency is taking steps to improve implementation, that NextGen is now on track and that the agency is starting to focus more on using these technologies to improve flight efficiencies and reduce flight time and fuel use, steps and a focus that should result in stakeholders realizing tangible benefits in the future. Almost all (75) of the 76 stakeholders identified challenges that they stated FAA faces in improving ATC operations and overcoming difficulties in implementing NextGen. (See app. IV for a list and description of the challenges for FAA that stakeholders identified during our interviews.) The six challenges stakeholders noted most often are discussed below.