Another drawback of wheeled bags for air travel is weight.

In my experience of lugging hundreds of kilos of windsurf gear around the world, I gave up on wheeled bags because the wheel systems simply added too much to the weight of the bag. With airlines clamping down on excess baggage and the fact that most airports have nice slippery floors I now prefer to go without wheels and save my pocket a little on the excess baggage.

Same goes for transporting bikes!