All perfect praise be to Allah, The Lord of The Worlds, and may His peace and blessings be upon our Prophet Muhammad and upon all of his family and companions.
Working at Aviation Company in tickets’ booking is considered recruitment and being a recruiter in it doesn’t entail a person to look for his private gain; rather he should be keen on the interest of the employer in the first place even if he had private customers or connections since he is already being paid against his efforts.
Further, any profit or gain taken by the employee while performing his job belongs only to the employer (Aviation Co.) for Allah, The Exalted said (What means):” And eat not up your property among yourselves in vanity.” [Al-Baqarah/188]. Besides, if you weren’t an employee in it, you won’t be able to get such a gain or profit nor to have customers.
Moreover, the purpose of the ticket discount given by the company to the employees is as a reward meant to be used either by them or by their acquaintances and not meant for selling.
Therefore, you are obliged to give back the 10Jd that you earned during your formal duty in any possible way, seek repentance and ask for forgiveness for what you did. And Allah knows best.