Can we have a personals on private flights. It would help in keeping track of your expenses which is important when you're using 

other people's money. Just for accounting purposes. 

It could read like below with the amount included.

Thanks

If the reason is because you are using other people's money, you already have a notification when you receive money from that person.

I think he means that it could be used to show that you actually used the money towards that? Like if your CL had you fly somewhere, you could show them the notification that you did fly.