First of all, Do you know what is the real of essence of ICO in the first place. ICO is for an initial funding for the start up project so without this kind of funding then a project will never be started especially if the devs team is not financially capable to start a project. Airdrop is a good way to distribute free tokens in different people but airdrop is use too by the devs to scam. Giving free tokens and then once listed on the exchange. OFC there will be a liquidity because of airdrop hunter selling their tokens which is what other newbie investor mistakenly saw as it's an active trading. Once the price pump due to newbie investors then the devs will dump their pre-mine coin and abandoned the project. There is so many history just like this one. So Airdrop alone is a big no.