Flying from Frankfurt to Bangkok offers nonstop connections with Lufthansa and Thai Air. The direct flights are the most comfortable solutions, but a bit expensive when booked one way. The reasonable pricing of Egypt Air was the reason for me to give them a trial during a trip in November 2018.
Frankfurt to Cairo
The first segment of the flight was from Frankfurt to Cairo on Egyptair 786 on a single aisle Boeing 737 aircraft (see B737 seatmap). The flight takes a bit over 3 hours and a full dinner is served. The following layover at Cairo airport lasted around 4 hours.
Cairo to Bangkok
The second leg of the trip lasts just a bit over 8 hours. It is a comfortable flight. The seats are in good condition. An overnight kit and head phones are given to all economy class passengers. The overnight kit is a surprise. Very few carriers bother to provide this comfort to their passengers in economy class. There is a foot rest for more comfort. Egyptair 960 is conducted on an Airbus A330-300 aircraft. The flight is not sold out, but pretty full.