The safest way to store your airdrops are hardware & cold storage wallets. These wallets store your coins offline, and therefore protect them from being hacked. There are a number of hardware wallets available. We would advise to use the Ledger Wallet Nano S or Trezor.
Not all cryptocurrency can be stored in hardware wallets. We advise you to store your crypto in wallets where you control your private keys. You don't want your free crypto to be stolen!
To avoid scams we have a few general rules:
Never give your private keys!
Use 2 Factor Authentication on your wallets
Be careful downloading wallets of smaller project, possibly use a Virtual machine.
Never click on links redirecting to wallets
Don’t use your main email address to apply for airdrops
Don’t re-use your passwords when you register on a website
Don’t send small amounts of crypto to receive your airdrop