I've tried just that but could not get it to work. If you manage to get it to work reliably this is likely the fastest mechanism you could make.

Some problems that you will run in to:

- the timing will need to be very precise

- you will likely need sensors before the stations

- Lego bricks come in all shapes and sizes and will respond unpredictably to air currents

- you will need a way to arrest momentum or they'll shoot right back out

Still, this is orders of magnitude faster than my contraption if you can get it work.