How heavy are solar panels?

And is it something that's improving at all? For example, putting solar panels on a variety of moving objects seems like a good idea at first, but would the weight of them almost make it a moot point, as the added weight means more energy is required to move the vehicle and a secondary engine such as a combustion engine then has to work overtime anyway?

As an example, how much can I expect a small solar panel, say 30cm by 30cm to weigh?

Solar roofing is 2-4 lbs per square foot or 10-20 kg per square meter, but that's including all the mounting equipment as well. Solar panels must be efficient for transport, as there is a solar powered aircraft that's flown around the world!

The silicon wafers are extremely light, so potentially very light, it's the plastic and other stuff that normally adds weights, but when built into a laptop it weighs almost nothing, and sometimes may even make an item weigh less.

As per my knowledge Solar roofing is 2-4 lbs per square foot or 10-20 kg per square meter, but that's including all the mounting equipment as well. Solar panels must be efficient for transport, as there is a solar powered aircraft that's flown around the world.