Translate the following English sentence to French:
"It is clear that certain businesses and a certain economic sector totally rely on night flights. If we asked them what would happen if there were no night flights, they are bound to say that they would have to close down their businesses, their activities would become pointless and they would no longer be able to offer their services."
Il apparaît de manière évidente qu' un certain nombre d' entreprises, qu' un certain secteur économique ne peut fonctionner sans vols de nuit et que, lorsque leur est posée la question de l' interdiction des vols de nuit, ils répondent : bon, alors, nous devrons arrêter nos activités, nos activités n' auront plus aucune utilité, nous ne pourrons dès lors plus proposer nos services.