is there an alternate power source for macbook air?

Recent MacBook Airs have USB-C ports, and on those, you should be able to charge using either USB-C port. The 13" and 15" M2 MacBook Airs have USB-C and MagSafe 3 ports. On those, you can charge using any of the three ports. This assumes that the laptop is in good working condition.

Charge your MacBook Air or MacBook Pro - Apple Support

ku4hx wrote:

No sorry ... there're no wind, natural gas or solar powered Macs. You have to have good old DC power supplied from a battery and recharged from an AC source.

There are solar-powered chargers with USB-C power output, but ones with enough capacity to be useful with a MacBook Air might weigh several times as much as the laptop itself.

https://www.outdoorgearlab.com/topics/camping-and-hiking/best-solar-charger

Note how the first (100 watt) charger on the list has "low weight" because it weighs a "mere" 10 pounds! Might be useful for someone driving to a remote campsite, but it wouldn't be fun carrying that and a lot of other things in a backpack.

If you were at a campsite so remote that it did not have wall outlets, odds are that there would be no WiFi hot spots. You'd need to bring along an iPhone (with hot spot feature turned on) or other mobile cellular hot spot to access the Internet.

Alternate as in what, exactly…?

Electricity is required.

No sorry ... there're no wind, natural gas or solar powered Macs. You have to have good old DC power supplied from a battery and recharged from an AC source.