There's no consistency on either answer. Newer planes may have electrical outlets. Some even have 110V. But that's not the norm. Some planes have 12V sockets like in cars. Others have 12V sockets that are smaller than cars. Some have no connections at all. It all depends on how old the plane is you end up on.
Internet access generally depends on carrier. And when it's available, I have seen WiFi access generally. You'll have to check your airline's website. But, again, it depends on the plane.
Apple offers an airline power adapter kit if you want to be able to use power on a plane.