Who hasn't imagined how wonderful it would be to be a bird? I have. Many a time. The freedom, the grace; mobility like no other, writes Debbie Hopkins.
Maybe it was thoughts like these that inspired Leonardo da Vinci in the 15th century, when he sketched designs for a ''flying machine''.
Or the ''father of the modern aircraft'', Sir George Cayley to pursue ''heavier than air crafts'' (before this point, advances mostly related to air balloons, often referred to as ''lighter than air crafts'').
The very term, aviation, is derived from the Latin word for bird: avis. Women and men across the world risked life and limb to design, construct and trial various flying machines, and to achieve new feats of flight.
The pioneer era (1903-1914), followed by the world wars (1914-1918, 1939-1945) drove much of the technological advancement, with the military adopting aeroplanes almost instantly.
Since 1980, aeroplanes have become bigger, faster, cheaper and more efficient. There are now more routes and more planes making their way around the world. But we're also seeing the realisation of some rather radical technological innovations; solar powered planes.
Solar Impulse 2, a round the world solar aeroplane, recently set new records for the longest and farthest flights in a solar powered craft. The plane flew more than 5600km in about 80 hours. This was also the longest non stop solo flight without refuelling in history.
The idea of powering an aeroplane by the sun is not new. It has been of interest to the aviation industry for more than 40 years.
However, recent technological developments have propelled solar aircraft into the public and industry consciousness.
Conventional aeroplanes, powered by reciprocating combustion engines and jet engines are still superior in terms of speed, distance and manoeuvrability.
But the solar plane has an infinite power source: there would be no need to stop to refuel. Imagine being able to fly from Dunedin (or Auckland) to London non stop! No pesky three hour lay overs, no missed connections.
There are also very clear environmental benefits to solar powered aircraft.
By harnessing the sun's energy, a renewable energy source, aeroplanes would no longer be releasing dangerous gases into the atmosphere.
High altitude aircraft travel in the upper troposphere and sometimes the delicate stratosphere, with severe implications for the global climate.
This is compounded by the fact that we're also flying more. Demand for air travel is growing, and despite technological efficiencies, total carbon emissions are rising.
Air travel is one of the most carbon intensive transport modes, equating to about 100-250g of carbon dioxide per kilometre (Direct CO2 Emissions per Distance).
While this isn't too much higher than some gas guzzling SUVs, we travel far further by aeroplane than we would by car. So, back to solar aeroplanes.
Imagine the ability to fly around the world powered by only the sun. I don't know about you, but that thought makes me rather giddy.
Flight, and the freedom and access flight offers, but without the guilt of harmful carbon emissions, without the knowledge that my actions are harming the global climate. I might never be a bird, but a solar plane might be a close second.
Debbie Hopkins is a research fellow at the University of Otago Centre for Sustainability. Each week in this column, one of a panel of writers addresses issues of sustainability.
