The following are some of the easiest way to figure out a scam airdrop
1. They will ask you to donate
2. They will ask for your private key
Feel free to add yours in case there are many more.
Best regards and happy airdrop chase.
Anyone asking for the private key is willing to scam you, airdrops doesn't need that because are free coins for the project.
Donations are always asked do not why it would be a sign of scam.