The most frequently used airline companies from Frankfurt to Madrid are generally
Ethiopian Airlines,
Lufthansa,
Austrian,
United Airlines,
Aeromexico,
Oman Air,
Air Baltic,
Delta Air Lines,
Lan Airlines,
All Nippon Airways,
Iberia,
Singapore Airlines,
Air Canada,
Vietnam Airlines,
Finnair,
Air Serbia,
Condor,
China Airlines,
Etihad Airways,
LOT Polish Airlines,
Scandinavian Airlines,
Air Europa,
Avianca,
Japan Airlines,
Air Nostrum,
Air China
are companies.