In-Flight Connectivity (IFC) services via satellite systems is expected to grow exponentially throughout the 2020 decade. The deployment of high throughput satellites (HTS) and mega-constellations, in geostationary and non-geostationary satellite orbits respectively, will result in higher demand and lower running costs. In addition to harsh environmental conditions, antenna systems must overcome important challenges derived from the operation in heterogenous scenarios, the associated regulations and the advanced features for passengers and airlines. One of the solutions proposed in this context is based on electronically steerable antennas (ESA), which can bring together high performance and reliability, multiple-beam operation, seamless handovers, and fast steering capabilities. Moreover, it can be integrated under industry standard ARINC-792 with low profile/drag solution to maximize interoperability and reduce fuel consumption. LESAF project explores the electronically steerable antennas to develop the key technology for the new generation of in-flight terminals.