Aeronautical industry deals with extremely complex and sensitive issues, the most critical of which being arguably aircraft safety during flight. For a variety of reasons and through different pathways, the integrity of an airplane might be compromised in such a way that passengers and crew might be at risk. In the case of military aircraft, this risk is largely aggravated in war zones.

Different aspects are addressed when designing an aircraft, and, in each of those areas, maintenance will eventually be required. Therefore, to keep an effective and affordable maintenance, real-time information for each of the different components of the aircraft must be provided. Sensors designed specifically for each parameter of interest are to be included in the primary design of the airplane. Optochemical sensing plays an important role in a vast number of fields, in most cases overcoming the limitations of other types of sensors. Luminescence-based sensors constitute a specific type of optochemical sensors, displaying a bunch of characteristics that render them unrivalled in terms of performance, sensitivity, reversibility, ease of miniaturization, and low cost. This chapter addresses the most relevant advances in luminescence-based sensors for molecular oxygen (both in fuel tanks and as pressure-sensitive paints), corrosion and wear, hydraulic fluid monitoring, and other parameters relevant to the aeronautical industry.