What is the ruling on benefiting from money that will be obtained in exchange for canceling some domestic flights, given the possibility of avoiding this beforehand by choosing a direct travel route?

There is no harm in you benefiting from the money that will be paid to you in lieu of internal tickets, as long as you are entitled to the ticket from your place of study, and the responsible authority approves and agrees to grant you the ticket, because "Muslims are bound by their conditions, except for a condition that makes lawful what is unlawful, or makes unlawful what is lawful."