Do you own a quarter of a million, or will you pay it for three years and you currently have part of it?
As far as I know, there are a lot of unemployed pilots because of the surplus to requirements. You can do a long research on websites, such as LinkedIn to have a view of the number of pilots who are looking for jobs and the number of airlines that have vacancies.
With this amount of money, you can do a lot of projects. However, will you lose the money for non-essential things? Or will you invest in the right way!
If I were in your place, I would start a business with 25,000 out of the 250,000 and see if things work out. Moreover, I will try to enlarge the business even if I had to postpone studying for one year.
If you succeed in the business field, you should continue to invest for one more year. However, in case you lost all of the money, you can easily make up, and it will not be an obstacle to enter the flight school.
You can consider the year of delay as a learning period, but on the condition that you will not use the remaining money until after a full year has passed, even if you needed 1 Saudi Riyal for the success of the project because the idea here does not relate to money but your ability to manage business and money.