The aim of this study is to actualize an in-situ measurement system of greenhouse gases using a UAV. This paper presents vertical profiles of CO₂ concentration as a measurement result with operation and long-term maintenance for a periodic flight tests. For this study, a new joint part with a single structure for improving strength of the sensor mount is developed. Moreover, routine maintenance to replace a router and periodic regulation of the analyzer is provided. After updating flight altitude permission over 150 m, we conducted flight tests up to 500 m. We compare individual linear correction and liner regression applied for vertical profiles of CO₂ concentration. We address that correction using linear regression has advantage to reduce burden for in-situ measurement.