Best way to determine future income?

Hello. Sorry if this has been asked, but is there a good way to determine how much money you'll have in 2-3 days?  I usually go through every one of my flights and take the end result and add/subtract that.  That's painstaking.  My weekend closing is on 11/18; I just want to see if I'll have enough money to add an aircraft right now or if I should wait. 

I usually just take the previous week's profits ("Adjusted EBITDA"), add that week's leasing installments and salaries, and divide that number by seven. That's what you can expect to earn in a day, minus whatever expenses are coming up in the financial schedule. If your airline is young & growing, that's even a conservative estimate, as this week's earnings are likely going to be higher than last week's.