Aluminium wheelchairs are approximately half the weight of the same size steel model. You are also able to remove the wheels and footplates of the alloy models to further reduce the weight.
Modern wheelchairs can be easily folded along the length of the wheelchair, so that the sides and handles are pushed together. Some wheelchairs have a folding back, which helps to reduce the size of the folded wheelchair. Most self propelled and transit models have quick release wheels which makes transportation easier. The leg rest can often also be removed. The heavier a wheelchair is, the heavier it will be to push, and the more difficult it will be to put in and take out of a car. Aluminium wheelchairs are lighter than steel wheelchairs but a little more expensive, but the weight difference when pushing or transporting the wheelchair will make up for the difference in price.