The FLAIR sensor system consists of an innovative 2D spectrometer system embedded on an airborne platform. Please, see the picture. The general working principle is the following: a broad spectrum generated by a specifically designed supercontinuum laser (emitting at 2-5 µm or 8-12 µm) (A) propagates through a multipass cell (D) filled with air samples at reduced pressure. The output spectrum with absorption features from different molecular species is dispersed by a quasi 2D