Q: does it hurt an air if I charge it on my macbook pro charger (60 vs 45)

You can use a higher wattage charger -- it won't hurt anything.

Using 60 watts power adapter wouldn't hurt a Macbook Air.

“Power adapters for Apple notebooks are available in 29W, 45W, 60W, and 85W varieties. You should use the appropriate wattage power adapter for your Apple notebook. You can use a compatible higher wattage adapter without issue, but it won't make your computer charge faster or operate differently. Lower wattage adapters will not provide enough power.”

https://support.apple.com/en-us/HT201700