nechaus wrote: tyres/tubes with helium ?
That would be useless. However-
If you happen to be in an area where the wind is relatively constant, and it might be in Brisbane, Australia, and if you are travailing with the wind, and you don't exceed the vector-calculated speed of the wind, and you tether a helium filled (experiment for size) balloon so that the total height isn't enough to reach overhead obstacles (<4m), you would assist your forward movement as with a sail.
You could even use cheap hydrogen if you are careful about ignition. Then you can afford to deflate the balloon for trips opposing the wind.
Please report back with your results.