If someone asks to send ETH to an address and promises an "airdrop" in return, it is clearly a scam. Airdrops are free, you don't pay for them. Plus it is really easy to pull out. Crypto is full of scam attempts, every day. You need to be very careful and never send funds, or give your private keys, for an "airdrop". Even if you invest in token sales, you need to do your due diligence to avoid scams.