This question already has an answer here:
For many visa applications, you need a flight reservation that shows you have purchased a round trip to your destination and back. But when you buy a flight there is a change your visa application won't be approved and then you already spent money. Yes, I know you can get cancellation insurance, but you have to do some extra administrative work before you get your money back.
So is it possible to make a flight reservation without paying for it right away and pay for it after you visa application is approved?