This Mac ships with a small Apple 30W USB-C Power Adapter. However, if you are running power hungry applications, 30W seems a bit low given that a lot of tablets are already in this range and even smartphones have started charging above 30W.
Using the GRL-C2 USB PD Tester and GRL-PSP Power Analyzer software from Granite River Labs, we can see it takes about 2.8 hours for the Apple 13" MacBook Air (2020) to report 100% battery, after starting to charge at close to 0% battery. During this time, the Apple 30W USB-C Power Adapter gets quite hot, reaching and uncomfortable 63 degrees C.
Interestingly, we see that the Mac still appears to be charging for another 25 minutes after the Mac has reported 100% battery.
This extended post "100%" battery charging could explain why the Apple 13" MacBook Air (2020) reports staying at 100% battery for about 13 minutes before the battery appears to start discharging.
When connected to a 60W USB PD charging source, we can see that the Apple 13" MacBook Air (2020) actually pulls a maximum of 47.5W for much of the 0 to 70% battery charging period. Initially the Mac max temperature on its surface gets up to a hot 50 deg C but settles to 40 deg C later.
After 70% charge, the Apple 13" MacBook Air (2020) starts to reduce its power to help improve battery life, and it takes about 104 minutes to fully charge the Mac.
After the Apple 13" MacBook Air (2020) is fully charged, the Mac uses just 14-22W while the Mac display is on without any significant power hungry applications consuming power. When Time Machine is used for backup, the Mac power consumption increases to 17-33W.
Given these power consumption levels, we can clearly see the advantages of using at least a 50W USB PD power source vs the Apple 30W USB-C Power Adapter when using power hungry applications or needing to quickly charge your battery. It takes about 1.7 hours to fully charge a battery depleted Apple 13" MacBook Air (2020) using at least a 50W USB PD charger vs 2.8 hours when using the in-box 30W charger. Users would certainly have benefited if Apple had included a much higher power adapter with the 13" MacBook Air (2020).