A recent Government Accountability Office (GAO) report to the House Transportation and Infrastructure Committee illustrates the FAA’s challenge in defining NextGen, which would transform 20th Century communications, navigation and surveillance into the advanced technology environment of 2025 and beyond. Cost is the overriding issue for both the government, with serious budget deficits, and industry, with its massive recent losses and the imperative to gain benefits from any future investments. But NextGen officials reported that full fleet equipage by 2025 could increase ground and airborne costs from earlier estimates of $40 billion to $160 billion. Extending full compliance out to 2035 would lower the total, but still remain significantly above $40 billion, a figure achievable only by reducing NextGen capabilities. Of the initial, mid and final segments–with respective completion in 2015, 2018, and 2025–only the first is defined and under way, embracing ADS-B and performance-based Rnav and RNP. Agency planners expect to finalize the mid-segment structure, potentially including DataComm and System Wide Information Management (Swim), in 12 to 18 months. But the final segment is only broadly envisioned, awaiting promising new technologies to mature.