Airdrops is very great source of income. But for this you need to find out legit and real airdrops. If you looking for some legit airdrops, then you can research all of them on thia forum.
No it's not a great source of income. You shouldn't even treat it that way.
Finding for a legit airdrop is also hard nowadays if you will just take a survey on most of the airdrop lovers.