## 2 Related Work  
For aircraft near tropopause altitudes over oceans and wide deserts, the only current practical and feasible wireless communication can be achieved using low-Earth orbit (LEO) satellites which provide limited broadband Internet speeds of few Mbps or even lower per user [7]. For example, Inmarsat satellites [8] provide global mobile connectivity for aviation where passengers onboard an aircraft are kept connected through broadband Internet services and the maintenance data can be sent also to ground for analysis and improved aircraft safety. Although LEO satellites provide wide coverage and global connectivity, they suffer from short orbital periods and visibility duration and requires also very frequent handover processes which complicates the system operation and reduces the availability of the network connections. For example, the recent deployed Starlink satellites [9] at 550 km orbit altitude or OneWeb satellites [10] orbiting at 1200 km altitude are only visible for a few minutes per satellite. In addition, the very high speed of LEO satellites results in large Doppler frequency shifts during flight which complicates the system operation and its related communication circuits. In addition, the other medium and geostationary satellite orbits suffer from even more operational difficulties including larger signal attenuation and longer delay time [11]. Recently in [11], \"GeoSurf\" polar satellites constellation have been designed at altitudes ranging from 1500 up to 35,876 km which provide communication over zenith paths with most of the advantages of satellites at different altitudes. However, the continuous movement of satellites requires complex communication infrastructure and inter-satellite link design. On the other hand, aircraft can also communicate with ground-based transmitters through air-to-ground connectivity (ATG) [12; 13; 14; 15; 16; 17; 18] using L-band digital aeronautical communication system (LDACS). However, the ATG communication channel suffers severely from multipath fading [16] and the L-band suffers from congestion [13] and did not become a suitable candidate for providing high-speed Internet connectivity for aircraft to support the three data domains required by ICAO [2]. Also, ATG suffers from atmospheric losses and ground terrains which impacts the communication link performance and the high speed of the aircraft along with the required very large number of terrestrial transmitters indicates that frequent handovers during flight must be performed. In addition, there is a lack of connectivity in isolated regions such as wide deserts and oceans where there are no ground transmitters are available. Another solution for aircraft Internet provision uses air-to-air (A2A) connectivity through aeronautical ad hoc network (AANET) which has been proposed to provide aircraft with Internet above clouds [19; 20; 21; 22; 23]. In AANET, the in-flight aircrafts are interconnected to spread the connectivity among them in an ad-hoc manner with enhanced capacity relative to ATG. Also, AANET may provide limited continuous connection over isolated regions where no ground transmitters are available. However, AANET suffers from many operational challenges [21] such as continuous mobility issues, congestion, threats, and propagation and interference impairments. Therefore, there should be an efficient and feasible communication network to achieve the goal of providing aviation with high-speed broadband Internet services to improve the aircraft safety, monitoring, control and provide passengers with efficient high-speed connectivity during flight.