I have a cistern supplying water to a mountain cabin. The cistern is full of water, but only a trickle comes out of the faucet in the cabin. It's a new installation and is far uphill from the cabin. Can an air lock cause this? How can it be fixed?

BTW, there is a pressure tank in the water line from when we pumped from a well. Could that be interfering somehow?

I don't like the phrase air lock. If a pump has water or other liquid freely flowing to it suction end, it will pump the water pushing any air out. If the pump has the smallest air leak between it and the water supply, the air will leak into the pump preventing it from pumping. Where the pump is located above the water level, the pump and the pipe down to the water usually needs to be full of water when the pump starts.

Usually an air leak means no water at all. A trickle is more likely to be a restriction in the line. If the old well had hard water and part of the piping is galvanized. That is where I would look first. Right at the faucet that delivers a trickle is another good place.