fuel

The Air Car uses compressed air to push its engine's pistons. Take a look at the video for more info.
(Running Time: 8:52)

Due to the global rise in the price of crude oil, people around the world have been affected by higher prices of gas/petrol at their local gas/petrol station. The cost of fuel has become so expensive (and possibly still rising), it has spawned a lot of jokes as seen in the images below:

Pic 1: Fuel gauge vs Price

Pic 2: Need a loan to fill up?

Pic 3: It costs an arm and a leg!

Pic 4: Man begs for money

Pic 5: Prices of Gas/Petrol

Pic 6: Bridal Gas Registry

Pic 7: Fuel vs Wallet