Here are two successful examples of airdrop:

Rebellious (REBL): https://bitcointalk.org/index.php?topic=2370176.0
Project Hydro (HYDRO): https://bitcointalk.org/index.php?topic=2778123.0

They have built a strong community through airdrop. A good community is very important in the crypto world. They will help promote the coin and vote to get listed on some exchanges for free.

Best wishes to you guys!