Don't sweat it. Airlines are far more interested in your flying ability than your academic ability. Get good groundschool passes across the board and your degree classification will appear as an anomoly in an otherwise sound academic career.
I know plenty of people who went through Oxford with me who don't have degrees, and plenty more who do, and who have a broad range of degree subjects and classifications. It is of interest to, but not crucial to, employers what you have done with your life and what you have achieved.
Don't lose any sleep over it, and if you want to fly just put it behind you and make the rest of your life a success.