Sounds like both will work for you, so I'd consider the non-processor differences, and ask if any of these matter to you:
ADVANTAGE MBP:
MBP has a somewhat brighter display (500 nits vs 400 nits, which might help when viewing the screen outdoors) (but otherwise its display seems the same as the Air's)*, somewhat longer battery life, and better speakers and microphone.
ADVANTAGE AIR:
Air is thinner and a bit lighter.
OTHER DIFFERENCES:
MBP has Touch Bar*, Air has physical function keys.
*Referring specifically to the MBP you have; does not apply to most versions of the MBP.
Air is dead silent, since it doesn't have a fan, though it's possible it may get warmer to the touch than the MBP (but I don't know). MBP should be fairly quiet under light use.
Keyboard feel may also be different--you'll need to check that for yourself.
Not sure if the trackpads are the same size (guessing they are, since the cases have the same width and depth).