Cymbidium orchids don't produce many aerial roots. Could you add a picture to the question? Normal new growth on Cymbidiums starts as a cluster of grass-like leaves from the base of one of the pseudobulbs--no long stems, no roots above the soil mix.

Cyms will produce aerial roots if they have outgrown their pot though - if this is the case then time to pot on. If they're attached to a clearly defined pseudobulb, you can very carefully separate this and pot it up individually to start a whole new plant. I prefer to leave them intact though and pot on the whole plant.