For communities around airports, the German Aircraft Noise Protection Act (FluLaermG) defines two noise protection zones (NPZ) for the daytime (6am – 10pm) and one for the night-time (10pm – 6am). Threshold values of aircraft noise exposure demarcate these zones. For residential properties within the NPZ, the FluLaermG regulates building restrictions and the eligibility for reimbursement of noise insulation, which, regarding the daytime, are stricter for NPZ day 1 than for NPZ day 2. On behalf of the Aircraft Noise Commission, Frankfurt, an expert opinion was prepared to evaluate the threshold values for airport regions in the FluLaermG from the perspective of noise effect research. For this, a threshold value system (TVS) for demarcation of the protection zones was developed based on results of a systematic literature review on health effects of aircraft noise. This contribution provides an overview of key results of the review underlying the TVS and outlines the rationale for the system. The proposed compelling threshold values for avoiding unacceptable health effects of aircraft noise for civil airport regions are 56 dB LAeq,day (NPZ day 1), 51 dB LAeq,day (NPZ day 2), and 44 dB LAeq,night (NPZ night).