There many airdrop these days which most of them are fakes,but there are some factors needed to considered before doing registration, I didn't do airdrop as I always do before when I finally know how things work.

First thing you need to considered is that, what is the aim of this coin? A good airdrop will come with the aim of solving a problem in our society, Using AVINOC as a case study, AVINOC is a consistent, integrated and permissionless base data layer for decentralized, transparent and worldwide coordination of business flights within the general aviation, to achieve optimal utilization and reduce costs significantly.

Secondly, a good airdrop must have white paper and social media accounts ranging from facebook, telegram, contact number, twitter, reddit, linkedin and so many social media which will be registered with their names, not like those crap airdrops where you will only fill I'm their ONE pager website and at the end of the day, they will ask you to send some ETH so as to get the coin, imagine if 20000 people send 0.01ETH. That is 200ETH.

These are the qualities I look before registering any airdrop these days just because I can't be wasting my data and time without getting anything in the end, hope this is helpful?