That is not the best answer. There are a lot of wrong answers here.
There are 2 kinds of taxes from a "earn" or "airdrop" which are both taxed the same way.
1) When you receive them they are taxed as income at the US dollar value they had when you received them. That also becomes your basis for when you sell them.
2) When you sell them you are taxed as long or short term capital gain on the profit (Sale price - basis)
